9.11.

When you're a senior in high school and three weeks shy of your 18th birthday not only is the world your oyster, but you think you own that world and that you're basically immortal.

I was a stereotypical senior in high school. I was over high school, wanted to do nothing but be with my friends 24/7, I rarely studied and I thought my hometown was the tiniest place on Earth.

Everything changed that Tuesday morning though as I sat in my "Transitions to College Mathematics" class with five or six of my closest friends and watched one tower catch fire as a plane crashed into the other tower.

When our vice principal came over the intercom to make an announcement about a plane crashing into one of the World Trade Center towers, I thought, "This has to be a terrible, terrible accident," but as we turned on the television and saw another plane do the same thing just minutes later, we all knew it wasn't a terrible accident, but a terrible tragedy that was far from an accident. This happened on purpose and while it was very much a direct hit to two office buildings thousands of miles of away, only known to me because they routinely showed the NYC skyline on "Friends," it felt like it happened in my backyard.

The first period math class that was typically a circus and platform for my almost 18-year-old comedy routines turned eerily somber. This class, where even my best friend, the homecoming queen and nicest person ever born, routinely got in trouble for talking, was suddenly silent, suddenly respectful of our teacher and suddenly fearful. In an instance we seemed to go from invincible to terrified. We went from knowing everything to knowing nothing in 18 minutes.

As the bell rang and we shuffled off to our next class, we learned that a third plane had crashed into the Pentagon. At that point, I was panicked. I knew if they could get to the Pentagon, they could get anywhere. The Pentagon was a military fortress. It housed all the people and plans that protected us from events like this.

The rest of that day and week are kind of a blur, but I do remember waking up that Wednesday and feeling different. There was no sense of security in anything any more.

I think that day, more than my 18th birthday, marks my passage into adulthood. But, it was also a day that proved to me just how young and naive I was and am. I'm not invincible and never will be.