Im really shy around the guy i like, how can i not be?

okay im really shy around guys i think its because when i was 14 i met this guy which i thought i liked but turns out he just wanted a shag, i was a virgin and wasnt wanting to change that! but i was to shy to say that i didnt want to and when while we were having i managed to ask him to stop and he wouldnt get off me and crying did not make a diffrence, im 15 now and have known this guy for ages which i really like and hes fingerd me and he wants me to give him a (i have never given one before, he doesnt know that) but i wouldnt give him one im not sure how? what should i tell him? how do i give him one? he doesnt like me being shy how can i not be so shy around him? thanks :) and please dont answer saying that im too young, thanks again :)