I have a lot of sexual fears, guys out there I need advise from GUYS ONLY!?

I'm 19 a sophomore in college and I have been having sexual fears for years now. I'm a guy and a virgin, yes its weird that my age mostly because I have had more like 50 offers from different girls. When I was growing up like in high school I focused so much on sports girls never noticed me. Now, I'm in college and girls love me, I mean I still play Tennis for my college and get straight A but girls have interest in me a lot now. I go to parties or even the pool and girls want to get sexual with me and I do send them feedback like kissing and touching but the actual sex scares me. Its frustrates me because I want to have sex but I'm scared. First, I'm terrified about the size of my penis, I mean I don't know if its small normal big I just don't know. Second, what if I'm just bad at it and can't pleasure the girl. Third, and last I'm uncircumcised so I'm scared that maybe the little vein in the back might break. This pisses me off badly I'm a Theatre/Law major and I'm very outgoing, funny, and not shy at all and I can't do this? I'm thinking WHAT THE ****! So please guys out there HELP ME!