Book that will help me grow up?

I had a very sheltered childhood, and I feel like I am emotionally stunted or something. I'm 27 and still feel and act like a kid. I'm afraid to talk to people, and whenever I'm out in public I feel like I don't belong and can't even make eye contact with people. I do almost everything cautiously because I'm scared I'm doing something wrong.

Are there any books that might help someone like me grow up and to stop being so afraid of doing what I want or saying what's on my mind?