You're ready, she is not ready. Do you know the circumstances behind her last relationship? It might have ended badly and she wants to breathe. I see you as a means that has aided her on a recovery journey, somewhat. Don't ruin it. You want to lock it in but she is locked out. Let time run its course. Pebbles were probably rough stones than constant running water over them made smooth. Continue been the sweet person that you're. Even if she does not date you ever, at least, you have a great friend in her. My talk might sound out of whack but it demonstrates you're not all about yourself, pushing or forcing your needs and desires over hers and trying to hard...there is a word for that...SELFISH. It shows, even if we never be together, I am kind, unselfish, and a true friend. But in this matter, I can promise you, she will come around. Keep running over her, restrain the urge (not easy) and be a good companion. After a good passage of time, whenever you want to bring up the subject, ask what happened to the previous relationship, that would guide your actions and how to approach the subject. Let the focus be on her, be truly concerned about her feelings and situations. She will notice. We all notice. Build it up from there. Your instincts will take the lead.