Before or After?

Mariah • Just me.
So I really like this guy and we have been talking for like 3 months now and I know he really wants to have sex but idk if I should make it clear that I'm not comfortable doing it till we are in a realationship, but I'm also scared if I say that he might get angry. I mean I do want to have sex with him but that not all I want it to be.