You can only get so many second chances in life to make things happen again man. You should be thankful that she is not someone's yet after all this time. From your writings i can sense that she is letting you know her availability to you. Act smart. Don't call or do face to face talk now coz she might get overwhelmed. By writing to her and let her know, i think she would understand, plus it would give her time to think as well.

Write to her tomorrow, you seems to be a good writer - tell her the story you told us. Do it tomorrow, if you get negative reply - tell her its APRIL FOOL man. Do it tomorrow or else this thing will hunt you for the rest of your life.