Hi Lincsguy,
xxazurexx has given some really good advice hear, about the strength of directness and honesty in you relationship, its definitely worth talking to her about how you feel. And don't be afraid to be completely honest and open
Before talking to her though, it might be worth taking an hour or so, by yourself, in nature preferably, and considering your life in full. Understanding that the part she plays in your life is not for you to dictate, or try to control, and reach a point where you are ready to let her go if she only sees you as a friend.
Given her circumstances, she no doubt has an unsusual relationship to sex. No, she isn't a virgin, but you don't yet understand (and may never fully understand) what sex means to her Make sure when you talk to her that you give her as much space as she needs to express this to whatever extent she wants. If you can tell her how you feel, and make your decisions, without trying to manipulate her, you'll find that the relationship will become stronger (even if its only as friends)...
Essentially, make sure she understands first and foremost that whatever happens, you wont stop loving her and respecting her, and that you aren't trying to turn her into something she doesn't want to be
Good luck!
Love one another, but make not a bond of love:
Let it rather be a moving sea between the shores of your souls.
Kahlil Gibran