Okay so im 15 going on 16 and ive been going out with this boy for a couple months, we aren't dating yet but I have really big feelings for him and he does too

he has had sex before but i haven't and I really wanna do it with him because I trust him and I have those feelings for him, he has asked two times while we are doing stuff but I always decline, I don't know if I should wait until we start dating or just do it before, it's either just wait it's gonna happen anyway or just do it because it's gonna happen anyway too

I'm also scared about when I tell my mum? What if she thinks bad of me If I did it without dating him? Ps im really keen to do it with him and I'm not nervous for the pain