Our first time. Advice please.

I have been thinking long and hard about the consequences that would result if my boyfriend and I have unprotected sex. We are at a responsible age to know better, I'm 20 and he's 22. We're both virgins and obviously we want sex to be great for us both. Now, here's the thing I'm overthinking about. I do not want to get pregnant at the moment yet we both want to go unprotected. I would love to have children and so would he but we're not stable enough to bring another life into the world. I know that contraception isn't always a hundred percent.