Sorry to revive a dead thread (not really ).
Yes, I dropped out in my junior year, when it became apparent that I wasn't going to be graduating. Then I went back an eventually graduated from an alternative high school when I was 20 years old.
My high school diploma never really did me any good. If I had it to do over again, I'm not sure I would have even wasted my time getting a diploma. But I guess the extra education was good for me.