What age is 'Young Adult'?

       Has anybody else noticed the growing number of people reading Young Adult books? I mean people aged like- 10 and 11 years old. What the heck. I just don't understand it. When I started reading Young Adult books years ago, I had to get a note signed by my mother, saying that I had permission to read books from the Young Adult section at my old library. So what is this crap with kids coming out of the library with YA  books. One day, one of these 10 year old kids is going to pick up a really mature YA book like Before I Die or even the House Of Night Series. Those books will be fantastic conversation starters at the dinner table won't they. It is true that some books that are labeled YA don't really need to be there. But it also goes the other way, some books are in the YA section that should be in the Adult section. I think we should all pray that these young, Young Adult readers realize that they should not be reading the Young Adult books and SOON.

What age do you think is a 'Young Adult'