I was in 6th grade in middle school, and it wasn't until about 1pm that anyone told us that anything was going on - we all knew that something was up because parents were picking their kids up throughout the day, and they'd come over the intercom with a list of 20 names ever 2 or 3 minutes of people to come to the office. My geography teacher simply said "I'm sure you know that weird things have been happening today, and the truth is we are under attack." Keep in mind this was in 2001, before 10 year olds had cell phones, so we didn't really have any means of communication.
At one point or another, flight 93 flew very close to or directly over my house, and my cousin (older by 2 years), who lives in Shanksville, saw the plane go overhead and then down over the treeline from his school classroom . . . . . spooky situation.