Potter as an adult
There is a parody of the Harry Potter books - Barry Trotter and the Unauthorized Parody by Michael Gerber. I haven't read it, or the other three in the series, but I believe that the story is that Barry has grown up, but refuses to leave school.

Read about my life at 16!
I had to share my sweet 16th with my brother. His band played, then we played truth or dare with our friends. Two girls made out, someone licked our deck, and I had to give a catsup bottle a bj. The whole thing cost about $50 and it was awesome.