Should we have sex?

Theres this guy who like me and we’ve been hooking up on and off for months and I think he wants to make it an official relationship, the only thing is that I’m 15 and he’s 18. All of his are all so much older. My best friend is dating one of his friends too and everyone is 18+ most of them are 20. I dont mind the age difference but him being that old makes me feel like I’m going to have to have sex with him to fit in. I cant talk to my best friend cause shesolder than me too. He’s a virgin and so am I, the farthest he’s gone is with me, I gave him a bj and he’s fingered me. I’m really nervous because we’re going away on a trip where there is no parents and lots of drinking, I’m already in trouble cause I just failed a drug test and my parents found out I smoke. I’ve gone on a trip with them before and we got so close to having sex, but we were drunk so I dont know if sober he’d pressure me. What should I do?