Unsure about sex!!!

I'm 15 and I've been with my boyfriend for around 3 months, but we've been really close friends for years! He's an amazing guy and I'm pretty sure that we'll be together for a long time. But I've never had sex before and he hasn't either. I know that I'm ready to have sex, and I'm fairly sure he is too, but I just don't know if 3 months is a long enough time to be ready for sex! I really need advice on this!