Fifteen years ago, everything changed.

We witnessed the worst terrorist attack on American soil -- live, on television. All of it seemed unreal; events we had never imagined.

That morning I tried to call my relatives who worked in the Twin Towers to see if they had escaped the destruction.

All circuits were busy. I kept hearing that recording.

The horror and fear of that day and the days that followed remains vivid. The stories and images of those who died, the heroes who saved others, the families who lost so much, set against a backdrop of tears and anger. As an American Muslim, or anyone perceived to be, there was the added trauma of feeling displaced, under suspicion, or worse, attacked, in her own country. In the middle of that fragility, there was also a sense of coming together. There was a unity in politics and within our communities that many of us had not experienced before.

The current generation of parents raising young children didn't live through the Vietnam War or the assassination of John F. Kennedy. It was Sept. 11 that changed us, and our country.

The aftermath led us into a terrible, prolonged war in Iraq. We sacrificed freedoms, a sacrifice lured by the promise of greater security. We turned a blind eye to human rights violations we scorn in other countries because we were told it was necessary to protect the nation.

Our children, born after those attacks, have never known what America was like before them.

By the end of this year, there will be about 60 million children, about eight times the population of New York, born in America since 9/11.

The oldest of these post-9/11 children are in high school, and more acutely aware of the political world around them, especially in this reality show of an election season.

How can they know the extent of everything that changed, all that was lost?

The post-9/11 children seem more jaded. The internet has exposed them to everything too early. They've watched videos of that day in classrooms. Maybe they didn't have a loss of innocence moment like we did, because when did they get to be innocents? Their generation's defining moment could have been the massacre at Sandy Hook Elementary school in Newtown, Connecticut. It wasn't the first school shooting, nor was it the worst, but the victims were so young. Adam Lanza, 20, murdered 20 six- and seven-year-olds -- first graders -- and six teachers. But unlike the seismic shift in priorities after the terrorists attacked, nothing changed after scores of school shootings. Well, we conditioned our children to be more vigilant and more afraid. We've taught them to always be on alert -- for school intruders, for online predators, for the next terrorist attack.

They've never known a nation at peace. They're growing up in an endless war on terror.

I asked my middle schoolers how they imagined the country was different before 9/11.

"Maybe there was less security," the younger one said, who spent much of the fourth grade worried about ISIS. The eighth grader wondered if there was less Islamophobia before.

They read the paper. Their generation has heard the rhetoric. They know how divided the country feels. They have their friends and schools and activities and typical adolescent pressures. But they experience it all within a chronic haze of anxiety that is our national landscape.

What a time to grow up.

Every year on this day, I remember the victims of those attacks and all the other losses that followed from those moments.

I mourn the lives lost and this seemingly endless state of war. I think of those who exploit national tragedies to tear us apart or to gain power or profit.

I mourn the country my children never knew.

Cynthia Tipton was having dinner with her family at Bandana's in the St. Louis area when she saw the look on her son's face. She knew what was coming.

Her 14-year-old daughter, Sophie, had been kidding around with her little brother, Noland. He got embarrassed by her mild teasing. He started screaming and crying. Loudly.

Noland, 10, has high-functioning autism.

His meltdown caught Tipton by surprise. She walked over to his chair, knelt down next to him, began rubbing his back and whispering in his ear: "You're being kind of loud. It's OK, buddy. Sophie was just teasing. Let's calm down. Let's be a little quieter. You're safe."

The screaming continued for a few minutes.

She felt self-conscious and could tell her father, who was dining with them, was embarrassed, too.

Then, it was like a switch flipped and her son calmed down. When the waitress walked over, her father was convinced another diner had complained and they were going to be banned from the restaurant.

That had happened once, when Noland was 4, and there had been a few times when Tipton had taken her son screaming and crying from a restaurant.

The waitress did, indeed, bring a message from another customer.

Another family had paid for their dinner. On the receipt, the strangers wrote, "Hi! We couldn't help but notice what a great mother you are and what a beautiful family you have. God bless."

Tipton, who recently opened an indoor gym for children on the autism spectrum and their families, was speechless. The family had already left, so she had no way to respond to such a gracious act of kindness.

"Being a parent is tough," she said. "Being an autism parent is really tough."

Strangers have no way of knowing that her child is not just being a brat. He has to work much harder than other children his age to control his emotions.

She came home Thursday night and posted the receipt and a note of thanks to the anonymous family on Facebook, hoping they may eventually see it. She wishes she could thank them.

"I am overwhelmed and humbled by your thoughtfulness," she wrote. "It was so unexpected, and yet it made such a huge difference to our family," Tipton said.

In an age when parents are often harshly judged by others, these strangers acted out of empathy.

Unlike the angry internet mobs quick to attack a child's mistakes, or to judge a parent for a family's tragedy, the interaction with those who have been in similar situations comes from a place of understanding.

Tipton, who gets teary-eyed talking about the diner's note, has been overwhelmed by people's reaction to her post.

"Just seeing how much it's uplifted other people ... it makes you feel good," she said. "Ultimately, I really, really hope that the family who did this for us sees this."

As the story spread of what happened in the restaurant, it prompted a heated debate among commenters about when a parent should take a child out of a restaurant. Parents of children on the spectrum tried to explain how some children respond differently to stimuli when upset. Tipton was clearly trying to calm her son.

Others made an argument that the other diners' experience should not have been negatively impacted, even if for a few minutes, by the outburst.

But the vast majority who responded to Tipton personally noted how much kinder the world would be if more people handled life the way the other family did.

Her father commented on Tipton's post: "The family that bought our dinner must have been angels from God. Regular people could not have looked at us with such compassion."

In fact, regular people can, and more of us should.

Once every four years, I wish my children would watch more television.

Normally, I'm fretting about them consuming damaging media messages. But during the summer Olympics, I want them to internalize every inspiring message.

You can do something that has never been done before. Look at Usain Bolt and Michael Phelps shattering records and claiming a spot among those called The Greatest.

You can fly higher than people have ever seen. Watch Simone Biles win five medals and pull off a signature tumbling pass that no one else in the world -- male or female -- can do.

You can wreck stereotypes. See Ibtihaj Muhammad, an American Muslim woman in hijab, win a bronze medal in fencing. And there's Dalilah Muhammad, an American Muslim woman in shorts, winning a gold medal in 400 meter hurdles for our country -- the first woman to do so.

You can carry the weight of history and still swim faster. Watch Simone Manuel dominate. As an African-American, she would have been forcibly shut out of public pools decades ago; today, she can win a gold medal in swimming.

You have opportunities you might not have known existed. Look at Ashleigh Johnson making those saves for our gold medal-winning water polo team.

Your hurts can propel you higher. Read Sarah Elizabeth Robles' tweet before she won an Olympic medal for weightlifting: "Things that used to get me bullied are the things that made me become an Olympian. Consider that when some jerk tries to tear you down."

Take heart in the diversity and camaraderie of the Final Five gold-medal gymnastic team.

It's not just the heroic feats of athleticism that I want my kids to notice. There are the stories on and off the field that reveal the human spirit.

Nikki Hamblin and Abbey D'Agostino fell in the middle of the 5000-meter qualifier. They took turns helping each other up. They sacrificed their chance to win to help a hurt competitor. Neither won a medal, but they earned the Olympic's Fair Play award for their sportsmanship.

In another moment of connection, two competitors took an innocent selfie. Hong Un-jong, a gymnast from North Korea, mugged for the camera with Lee Eun-ju, a gymnast from South Korea, and it captured a story of friendship that transcends borders.

Most inspiring were the 10 athletes competing on the Refugee Olympic Team. They had fled Syria, Ethiopia, South Sudan and the Congo, and survived conditions most of us can't even fathom. They left wars and persecution, looking for safe havens in a world largely indifferent -- or even hostile -- to their plight. The world turned its back on Yusra Mardini, a Syrian teenager who crossed from Turkey into Greece in an overloaded inflatable boat. When its motor failed and the boat took on water, she and her sister jumped into the sea and swam for three hours while pushing the boat, saving the lives of the other passengers.

The refugee athletes may not have won medals, but they won our hearts.

These stories are the anti-venom for a poisonous election season.

I wanted my children to learn from the lowlights, too. You can be a world-class athlete and still turn yourself into a national embarrassment. Medals don't look good on liars.

But I prefer to focus on my personal heroes from these Games: the 40-somethings, the moms, the marginalized. They showed us over and over again that you can compete with athletes half your age.

How can you not be in awe of Oksana Chusovitina, who has competed at every Summer Olympics since Barcelona in 1992? A seven-time Olympian who, at 41, became the oldest gymnast in Olympic history, competed alongside athletes her son's age.

I cheered for Kerri Walsh Jennings, still winning medals in beach volleyball at 38.

And there was Kristin Armstrong, a day before she turned 43, becoming the first American woman to win an individual event in three consecutive summer Olympics. She is the oldest woman cyclist to ever win gold.

"People have asked me, over and over, 'Why? Why am I back?'" she said in an interview with NBC Sports. "And it's because I can."

Like nearly everyone else in the world, I'm never going to be an Olympian. But we can share that spirit.

Because we can.