Boyfriend issue..

Soo I guess you can say I've been dating this guy for 4 years off and on now.. He's amazing and I love him a lot.. We are both 17, him being exactly a year older than I am. Well he wants to take our relationship to the next level, he wants to actually cum in me.. I'm not on any birth control because my dads completly against it, so I'm afraid to let him do it. I just don't know how to tell him. I think we should atleast wait until I turn 18 and I can get birth control without my dad saying anything.. Granted I want to do this with him because it would be special I just don't want to get pregnant.