Why do I have a curse with girls?

This has been an ongoing problem for me my entire life. I have this strange curse with girls and i cant figure out why i do. First off i am a complete coward when it comes to talking to girls, even when they are nice to me and start the conversation. I don't freak out but i become very shy, talk quietly, fidget with things, blush, become nervous (especially when i look into their eyes) studder, and other strange things. The other thing i should add i guess is i have been rejected 28 times (proof that i havent given up on this situation). The girls at my former school were not what you call respectful.Now that I'm at a new school its different. I am the guy who everyone seldom talks to, you know the ghost in the graveyard, lone soldier, etc. Whenever i wish to become friends with a girl or try to ask them out they take every step to avoid me. All i want to do is reverse my unfortunate luck with girls. Can someone please help me?