Hey good luck. I've told quite a few new doctors lately (I've had some recent non-trans-related surgeries, and my insurance status keeps changing, etc), and the first two I told reacted very differently. My primary care doc I went in and just said casually - more casually than I felt - "hey, I'm transgendered, you don't have a problem with that, do you?" and he was totally cool. Within a few appointments he did admit that he felt way out of his league, and he referred me to one of his colleagues for hormone management (and to a mental health agency for antidepressant management), but he was never disrespectful or indifferent.
The other doctor I told was when I wasn't really out yet, but I figured she'd be safe to tell because she was a gynecologist, and they have to know more about gender and genital mismatch than anybody, right? Lol I was so wrong. The things she said left me feeling invalidated as a human, and I cried all afternoon.
Again, good luck. Be steady in yourself whether they treat you right or not.