I'm 18 years old. I am really outgoing, occasionally I do put up a wall. I am not hideous, well I don't think. Guys hit on me and all that cheesy stuff. SO why doesn't anyone ask me out? I have been asked out in the past,but I do not like any of the guys,and I didn't feel like giving someone I was not attracted to a chance, which makes sense considering I wasn't desperate. But NOW I just feel not normal. I am 18, still single, and to be quite honest, I am feeling pretty undesirable, which sucks.
So what the heck am I doing wrong???!!!

Probably nothing. Maybe guys are intimidated by how awesome you are. Maybe they're afraid of rejection because they think you're too pretty and outgoing for someone like them. Don't worry about it now, because you're still young. Just live it up :)