I am with Jan on this one, it is crap, and not all it is cracked up to be. The main thing I have noticed as an adult is that time moves a lot faster than it does as a kid, and the years just fly by. It has been 21 years since I left school, but does not seem 5 minutes. Glad that there is no such thing as time in the next life!
"Growing old is unavoidable, but growing up is optional" I can not remember who gave us this quote.
Stay a kid if you can, all your life; that is what I would do.