Am i rushing into a relationship?/am i supposed to trust him?

i've been off and on with this guy i've had the hugest crush on for what feels like almost 4years. we rarely see much of each other because i went to an all girls school & he went to an all boys school and when are schools intermingled i didnt hang with him b/c he was a jock and i was nerd and my guy friends at the school were literally intimidated by him. whenever i came around he gave me the best hugs and smiles and my body pretty much feigns for his touch. before school ended, we ended up on the same bus together heading into the city and my feelings came rushing back. and since then he's been talking to me and trying to get in contact with me so i can be with him &go out. but the thing is he saying he wants to go out with me but he wants me to have sex with him before he goes to stay with his family members for like 3weeks. its not that im scared to lose my virginity but he'spromising that nothing will change after he comes back. and idnt know what to think because girls are always on him & he never had relationships with most of them , but who knows what happens behind closed doors ? what he says is convincing but its not like i can ask my bestfriend b/c we've traded guys as much as we traded clothes. and ive seen many relationships where the couples dont have sex for the 1st 6 months and then as soon as they do, they dump her *** on valentines day . i have everything to counteract my thoughts. im not a dumb person. my life isnt perfect... nothing is. idk who to talk to.. i want to be in a relationship with him but does sex really have to play a role so early ?