This is normal. I was never comfortable enough with my first boyfriend to let myself orgasm, and with my current boyfriend, the first couple of times we had sex, he wasn't able to get off. We got the hang of it after a few tries together, though. The important thing is being comfortable with one another. Relax, watch a movie or something, don't try to force it. Try masturbating together, just to get used to orgasming around one another. Then start helping each other, and eventually work up to taking over for one another.