Teenage son

My teenage son (he’s in 10th grade) and his girlfriend (also in 10th) have been dating for a year. They are very close but are also in a healthy relationship and are very in love. I have no proof to say this, however just wondering, do any of you think they could potentially be having sex? I’m afraid to straight up ask him as I’m afraid he will resent me for asking. What do you all think?