No offense to Johanna but this is seriously bad advice!
I Can only tell you that you have gotten great advice from the GGs who have responded in this thread already. You should listen to their advice they really know what they are talking about.
What people need in comming to terms with gender variant people is time. We live with ourselves and desires and as difficult as they are or have been we have had time in most cases years to cme to terms with who and what we are. Once we reach a point where we are ready to accept our selves we want everybody around us to understand in 5 minutes. Unfortunately it doesnt work that way. Think about what you have gone through in your life, All of the ups and downs, emmotional highs and lows, guilt , fear, and shame, binges and purges. Everything that caused that stress in your life, the questions, Whats wrong with me? Why do I do this? What if they found out? are the same things that effect the people we love. If you love this girl don't push as hard as that is. Give her time and space.
I hope it works out between you she sounds pretty great!