My only advice is this:
Getting to know each other and being open really does help. But as it's your first, unless you're incredibly lucky and are really, really compatible with your BF, try and see the relationship as more of a learning curve than anything else. Only worry about breaking up if things start going wrong with the relationship; Otherwise, simply go with the flow and do what you feel is right, and take it easy. Never force anything, and never jump to conclusions without proper evidence.
If what you end up doing doesn't turn out to be right, it may get you down at first, but depending on how much your relationship meant to you, the scars will heal and you'll always recover afterwards. You'd of then you learned your lesson. Just remember that there's always plenty more fish in the sea.

Also, try and use this opportunity to find out what you really are looking for in a relationship. Discover yourself some more.
Remember again not to take your first relationship too seriously unless you're really 100% sure he's Mr. Fantastic after a number of years of you two knowing each other. Don't be blinded by love, and don't commit yourself to or get tied up in anything that you won't be able to get out of easily unless you're really, really, 100% sure you want to do them, for example having children, getting married or chosing to live with this guy.
And whatever the hell you do,
USE PROTECTION DURING SEX and
DON'T CUT YOUR WRISTS IF YOU BREAK UP.
Apart from that, good luck! Keep in mind that relationships are wild, spontaneous things with two sharp edges and a warm, fuzzy middle. They give just as much pain as they give pleasure. Hope this helps. :P