I had no Choice. I was never going to be a boy. I was, still am, and always will be, 100% female. The same goes for you.
It will begin as a harmless fantasy. A feminine mirage which all too soon will consume your sexuality. Then it will conquer your interests, thoughts, hobbies.....personality.
Finally it will take over and you will be her. She is strong and will survive. Do not fight back, because you know you are her.