On Sept. 11, 2001, 2,977 innocents went about their daily business, boarding commercial airliners, traveling to work, or suiting up at local firehouses and police stations. Cornflower blue skies offered no portents of the series of terror attacks that would soon claim their lives.

Throughout the day, the world would watch shocking footage of those lives being stolen in New York City, Washington, D.C., and Shanksville, Pennsylvania. For a time, we were wrenched from our reverie that our American way of life rendered us untouchable.

I was 14 when I arrived home from an early dismissal on Sept. 11 to find my father, a former naval aviator, sitting in his wheelchair beside our large box television set. We exchanged no greetings. I sat beside him in silence while we watched events we had already witnessed as they unfolded over and over again on the screen.

We saw a commercial plane filled with commuters slam directly into the World Trade Center’s North Tower. We listened to newscasters’ tones become clipped and fearful after the second airplane’s impact stripped the innocent shock from their voices, and our psyches. Under our unaverted gaze, human beings stood on the sides of skyscrapers and made the unfathomable calculation that whatever hell awaited them inside those walls was more terrifying than jumping from heights humans could not expect to survive. We bounced along with juddering cameras that captured the horror-stricken faces of evacuees, plastered with blood and a thick layer of ash, as they escaped the burning World Trade Center towers. We felt something inside ourselves collapse alongside first the South, and then the North Tower. We stolidly witnessed the breached walls of the Pentagon, its complex system of rings laid open, jagged and charred. We did not look away from the smoldering, scattered remains of Flight 93, brought down by patriots in a Pennsylvania field. We sent whatever hope we could muster with the never-ending stream of first responders who continued to run toward the emergency sites, intent on providing life-saving aid even at their own peril.

Finally, my father turned and broke the quiet of our solemn vigil. “Your world will never be the same,” he said.

In fact, both our worlds would change. My father lost three friends on Sept. 11. Ken Waldie, his classmate from the United States Naval Academy, was aboard American Airlines Flight 11, the first plane to be hijacked and flown into the World Trade Center. Tom "Stout" McGuinness was Flight 11’s co-pilot and first officer. Charles "Chic" Burlingame piloted American Airlines Flight 77, which terrorists flew into the Pentagon.

Surface-level changes started immediately. Collective mourning and outrage gave way to a temporary burst of national unity as we bartered our privacy for a frenzy of security procedures meant to make Americans safer.

But the events, as my father foretold, were particularly consequential for members of my teenage peer group. Though we were too young to track all the pieces moving around us, we could never cast off the images of terror and the palpable atmosphere of insecurity and fear we found ourselves inside. For many of us, 9/11 brought on an early and immutable transition to adulthood.

Not months after the attacks, I sat on the school bus with a good friend. In the dreary early darkness of a winter afternoon, he veered from our usual dissection of middle school dramas when he told me he had decided he could never get married. Warily, I asked him why not. He explained that he wanted to become a Navy Seal. It was a dangerous career path, and if he lost his life in service to his country, he felt it would be cruel to leave behind a devastated wife and children. Through a flood of tears, I tried to rationalize with my friend that he could be a Seal and a husband and father. He would not be swayed.

In the eighth grade, I had witnessed the first of my friends turn from teenager to adult in Sept. 11’s aftermath.

In the 18 years that have passed, many of my friends and family members have responded similarly, answering Americans’ cries of woe by entering our country’s service. I have seen them enter West Point and the United States Naval Academy, fully aware that graduation would inject them into a roiling multifront war. I have watched them choose to enlist or pursue officer training after school, after college, and even after entering the workforce. They have gone on to fly jets, jump from perfectly good aircraft, or fast rope out of helicopters. They have grown accustomed to rucking large loads across tough terrain and have directed or assisted platoons of men in pursuit of al Qaeda and its sister terror organizations in Afghanistan, Iraq, Syria, and other dark corners of the world. When American leaders lost the appetite to continue fighting on Afghan battlefields, my friends fearlessly trained the foreign forces who had begun turning their guns on their American trainers in deadly green-on-blue attacks.

Others reacted by becoming first responders. Even when the nation’s appreciation of those everyday heroes seems daily to dwindle, members of my peer group have paid homage to their memories by ensuring they will be at the ready in the event such horrors transpire again.

A number of those who came of age on Sept. 11 became the heroes our nation needed. Spurred on by the sense of duty those terror attacks imparted, they lived “Never Forget,” and they were prepared to give their lives for America, should the need arise.

Every year on Sept. 11, the nation recalls the awestruck horror we felt on that unforgettable day. We remember the victims, and the heroes. Some of us yearn for that breathtaking unity our country experienced in the days after the devastating terror attacks, particularly as divisiveness and incivility now pervade our national dialogue.

This year, when we think about the day’s significance, let us also celebrate the generation of selfless young men and women who came of age on Sept. 11, who saw the devastation our enemy had wrought, and raced toward the hurt and darkness to give of themselves in service to their fellow Americans.

Beth Bailey (@BWBailey85) is a freelance writer from the Detroit area.