sex for the first time, advice please

I'm 16 years old, I'm a virgin. There is someone who I have been close with for a long time and we have discussed sex but obviously never done it. I know all the "if he cares you for then he won't care if it's good or bad" type thing, but he isn't a Virgin, he's 17. We care for each other a lot. Can someone just give me some tips on having sex for the first time?