My earliest memories are of the ducks in our backyard in Spain, and the water buffalo (water tank on a trailer) parked at the end of the street when the water was turned off. I moved from Spain the summer before I turned 3. Those are true memories, as there are no pictures to remind me, and even when talking to my mom, she had to think to remember them, so she had not told me about them. Plenty of others that i consider assisted memories...pics of me in a mop bucket, stories of me going door to door asking for cookies, or when I walked off base to go visit dad at work (on base, but had to go out of the base housing side and back in the airfield side to get to his hanger...they caught me at the airfield gate trying to sneak in).
As for 9/11, I was home, woken by a call saying work was cancelled (I worked outsourced AOL tech support at the time). Watched TV, including the second tower strike, and updates o the other two planes. Eventually turned it off and started calling family. Wife was at work the whole day, and with no work and being awake (I would normally sleep most of the day, worked 4pm-1am shift), I would taken have advantage and played a ton of EQ. I did log in for a bit, just to chat with friends and guildies...no actual gameplay that day.
The world did change that day. Mostly for the worse IMO. Airport security all over the world is a much bigger pain that ever before. Privacy is a thing of the past (not just governments...Google and Facebook, etc. are a big part of that as well). Uber-nationalism, tribalism, xenophobia, partisan politics (alway present, but worse than ever), and so on. I hope the next generations do a better job than mine or my parents. I have faith in my kids (well spread in years....28 and 9), and I hope the rest of their peers stand with them and turn things around.