Hi Serena,
As Suzi said, a doctor's care is only as good as the information he or she is presented with. You are going to a GP and endocrinologist to help you with your medical needs. Hormone therapy is not trivial stuff. If you are coming out to your professor, and explaining to the housing office why you would feel better in a gender-neutral dorm, you should be honest with your medical providers as well.
As far as asking your professors to call you by your preferred name, that's not a big deal, or at least it shouldn't be. I don't know what type of classes you will be taking, but the times the instructor may call upon you by name in class may be close to zero. I taught organic chemistry to undergrads for four years . I had 50-70 students in a lecture hall. Names never came up, except perhaps during office hours, which is a more private setting. I don't think I ever had a trans student, but if I did, and they asked me to call them by their preferred name, I would have had no problem with it.
If you have the opportunity to live in a gender-neutral dorm, you should absolutely ask if it makes you feel more comfortable. College can be one of the most exhilarating and wonderful times of your life. It is a coming of age for most. It can sometimes be a little scary, especially combined with transitioning, but it could also be the best possible time. You will meet other students coming from all kinds of different places, with all kinds of different backgrounds, with everyone trying to create an identity, in one way or another.
Ah, to be young again! In some ways I envy you. It's the beginning of the rest of your life, something you will remember forever. You are going to have a wonderful time.
Wishing you all the best,
Terri