Chances are, you won't hurt, you won't bleed, and you will enjoy yourself quite a bit.
Condoms are plenty effective if you use them correctly. Use lube because it decreases the chances that they'll break. And if you are concerned, you can keep some plan b around in case one breaks while you use it. That's really the only way something can go wrong, all condoms on the market now are rigorously tested and nothing gets through as long as they are intact.
But yes, make sure he has no std's, and you might want to think about getting on a different kind of birth control if you think that is for you, mostly because you might get sick of using condoms! You sound like you will be fine.