Do not ever have sex just because you think he will get bored. Do it when you know you are ready. I don't believe 15 is old enough to know when you are ready, but hey it's your life and not mine. Just don't get pressured into doing it. Do it when it feels right to you. You can never go back and undo it.

and PS: Never believe a guy when he says he knows the "pull out" method. Doesn't work, my friend still got pregnant with twins.