When the time comes, you're gonna have to man up and tell her how you feel about her. Be smart about it. Don't go through life in regretting on not knowing about "if." That will eat you up and linger in the deep pit of your soul.
If she's everything you say she is, then she'll either accept it or decline.... but with dignity and respect to keep a friendship because its that much of an importance for her as it to you. Take all that as my simple humble opinion. Good luck.