Getting used to sex?

I’ve sort of had sex a few times (3) but it was only like 5 minute quickies and I never came. It hurts really bad whenever any guy puts it in me. My hymen broke on the first time and I also don’t finger myself or let other guys finger me. Is it normal for sex to hurt like that? And will it always be like that or will I loosen up? Also, what are some ways to get used to it so it doesn’t hurt? Also, I don’t know if age has anything to do with vaginal tolerance/development/width/stretch, but I’m 15.