Laurenza, you will be fine. Being honest and clear about your needs is the best thing, and to have your story clear and coherent.
Being trans requires us to be patient, maintain a sense of humour, and be resilient to the occasion setbacks we encounter:
I needed to convert my UK passport to my new gender. I consulted carefully, asked the Passport Office for advice, and flew to London last week to do the change in-situ. And you know what, the official advice I received was wrong on several points, and my application was rejected - I had to return empty handed. I could have cried, and almost did, but I used the opportunity to see my nephews and go shopping with my sister for new season's clothes. It was not so bad.
So smile at your endocrinologist, and make them your friend.
Good luck!
Julia