That is a scary place to be. I told my adult daughter and I thought she was going to run for the hills, but after it sank in overnight she has been so excited to help me with clothes, makeup, mannerisms and the whole feminine aspects of my life. On another note when I told my wife I did pule and then cried for about three hours.
Just be careful and honest and you will be alright and probably have an even closer friendship.
Wishing you the best.
Davida