Hey hun, it's going to be okay and I applaud your courage in doing what you feel is right in your life. This is my suggestion to you however, and you may take it or leave it:
Nursing school is a very stressful time in ones life. Making the big change is just as if not more stressful. If I were in your position I would wait until after I graduated then decide to move on to making the MTF change. Not because it would be easier to be accepted, but only because right now you should be diverted all your attention on doing well in school and once hormone therapy start and everything like that... emotions will fly.
I hope you all the best, from one of your glbt family.
P.S. I want to stress that if you decide to postpone this, it should be (in my opinion) for your OWN emotional and academic reasons, not the schools. Personally I feel you shouldn't give a damn about what they think about you. If you do decide to go through with it and they make it hard on you, you will persevere... and if they step over the line then it will become a legal issue. It makes me sad that in today's day and age we still have to worry about things like this. Just the other day there was a car in front of me all the way to school with a bumper sticker that was very homophobic and by now I've learned to just laugh at the stupidity of bigotry. You'll make it, don't worry.