Alexis,
Wishful expresses very well, the wonderful effects of oestrogen, on the mind. Your last post makes it sound as if, at heart, you know you are trans. If you really want to block the remaining changes tostesterone can bring, even at your age, you shoud seriously consider black coshosh. now. Apart from the changes, you worry about, you could still grow another couple of inches and the size of your chest will probably increase.
I would urge you to go to your local support group. Not only will you have the joy of being treated as perfectly normal, also, if you talk to some of the older ladies, you will find some very tortured souls, torn between loyalty to their wife and family, and their need to be a woman. You are in a position, where you can avoid getting yourself into such a dilema.
I wish you all the best,
Chrissie