Personally, I wouldn't wanna deal with this situation at all.
At 18, she still has a lot of growing up to do and still has to figure things out.
I agree with Reincar. At 21 and 18, though you may think so now, odds are she is not the woman you will spend the rest of your life with, and Hell, maybe not even the rest of the year with.
Based on what I've seen you say about her in the other thread, she seems like a very good girl, but no matter how rooted she may be in her African believes, she's still over here now and has North American woman tendencies. She's gonna wanna explore other men and "live life" because that's what women in our culture are told they should do.
Her first time is gonna mean a lot to her and, personally, I wouldn't want to be THAT guy because it's going to create a lot of emotional baggage on both sides (and also because, like someone said earlier, I don't like virgin vaginas).
You said she's not even suckin you off though? C'mon fam...