I was a senior in High School. By the time I knew what was going on, it was already 12pm NYC time. See, I lived in CA, and oddly enough, I didn't have my radio on, nor did I turn it on when I was driving to school. I remember going to my econ class, and everyone was "normal"--I remember the class clown asking about "What happened this morning, I think we should talk about it.." and my teacher saying "My sister is an AA flight attendent, and we don't know where she is. This probably affects me more then you guys.." I asked my neighbor, Bob, what was going on, and he said "I don't know."
I walked to my Modern Lit class, like normal. And my teacher had the TV on and was bawling. I asked her what was going on, and she told me.