What should I do about these boys!!!!!!!!!!?

Please help me all these boys in my school are always flirting with me but the guy I like ( who was my best friend) is all of a sudden being a jerk to me for no reason to day I don't know what to do!!! and I really don't even know if he broke up with his girl friend but I heard he did! Maybe his girlfriend doesn't lke that I'm his friend!! Should I forget about him or not should I ask out the other guy I like ( one of my friend's ex-boyfriends!!! ) or should I ask him why he is being mean to me all of a sudden and share my feelings with him when I don't know whether he has a girlfriend or not????!!!!!P.S. I'm only twelve years old do you think that is too young to be dating???!!!