I also know readers who will never see the movie of a book they've read because it ruins the book for them. If that's you- I get it, and don't read the rest of this post!
Personally I love to watch the movie, if only to criticize it, or I might even end up loving it (For example, I love The Hunger Games movie almost as much as the book.)
I'm mostly writing this post as a way to remember all these dates of the many movies coming out in 2013 based on YA books. There are so many this year, I think Hollywood is running out of their own creative ideas, so they're turning to YA books. I'm not complaining!
Beautiful Creatures
Release Date: Feb. 13 2013
IMDB: http://www.imdb.com/title/tt1559547/
The Mortal Instruments: City of Bones
Release Date: August 23, 2013
IMDB: http://www.imdb.com/title/tt1538403/
The Host (Not technically YA, but still)
Release Date: March 29, 2013
IMDB: http://www.imdb.com/title/tt1517260/
Percy Jackson: Sea of Monsters
Release Date: August 16, 2013
IMDB: http://www.imdb.com/title/tt1854564/
No trailer yet.
Ender's Game
Release Date: Nov 1 2013
IMDB: http://www.imdb.com/title/tt1731141/
No trailer yet.
Catching Fire
Release Date: November 22, 2013
IMDB: http://www.imdb.com/title/tt1854564/
No trailer yet.
Honorable Mention:
The Hobbit: An Unexpected Journey (doesn't really count as YA or 2013, but I'm still uber-excited!)
Release Date: Dec. 14 2012
IMDB: http://www.imdb.com/title/tt0903624/
The Great Gatsby
Release Date: 10 May 2013
IMDB: http://www.imdb.com/title/tt1343092/