A 13 year old babsat for a 12 year old.
I think that's your first problem.
Nahh, (no to crush and no to wierd). He's just discovering girls. You're like a whole new country. Imagine being Christopher Columbus and discovering America only America is soft and warm and makes you feel kind of tingly when you're near it.
He may have some disorder that makes his development slower then others just be kind to him!
Young boys aren't yet wily enough to dismiss the advice they're told about "being forward and yourself." Tact is a learned quality.
that must be it.. he had crush on both of you :)