SEX HELP PLS

ma
Ok girls! I need some advice. I am 16 years old and more then in love with my boyfriend. I want to start having sex with him. I am not on the pill and i'm nervous about getting pregnant. We will ALWAYS use a condom. I was thinking of starting off by him going in and doing a few strokes and coming out just to get use to it and then I would build up to it (so sexy i know) Any thoughts on that? Also do you guys think that lube will make a huge difference ? If yes i know i can't use like coconut oil cause it will break down the condom, so any ideas of good lubes and where I can purchase? Thank you lovelies!! 
ps. 
what position would be best for this?