I was in high school. We rarely watched TV at home, so I heard about it when I showed up for school. Watched the 2nd plane hit on live TV in one of the classrooms (I forget which class).
I still remember first hearing about the Patriot Act, and thinking it was basically what the terrorists would have wanted. Our own government taking away our freedom, the very thing they despised. I sounded a bit jaded back then (especially for a teenager) saying the Patriot Act would do more damage than the planes did, but I think I was (unfortunately) right.
I visited New York last month. Didn't get to go to ground zero, but out there, everyone knows someone who was directly affected by the attacks. Such a shame; I still pray for the families now and again.