21 year old virgin.

So I'm 21 and I've never had sex. In the past, I've had encounters where I almost had sex but I just said no even though I kind of wanted to have sex. I'm superrrrrr self conscious about my body and I think I would just feel gross if I'm naked in front of a guy. Anyways, there's this guy I really like that I've been seeing but I'm still scared about having sex with him. Any tips?