orgasms?!

hi so i have only had orgasms from clit stimulation and i've never had penetrative sex and was wondering how many people have actually orgasmed from it? my boyfriend and i are probably going to have sex soon (i'm not expecting to have an orgasm the first or even first few times i just want to know how possible it is). so i was just wondering how many of you have actually had an orgasm from penetrative sex. my boyfriend fingers me and it feels really good but i just don't think he's ever done it long enough for me to cum. i've done it by myself too and i just feel like it would take too long and i'm not even sure if i can.