What to expect first time sex

I was just wondering what it's like to have sex for the first time? I'm scared the it's going to hurt or he don't like my body. What if I really can't please him or he just wants it now. I don't know I'm really curious. How do I know it's ok to have sex or when he wants sex? Do you have sex in light or dark place? What should I really know before I have sex?