ivallesa,
If you are scared, it means your being smart. This is not to be taken lightly. Your doctor would be more concerned with a nonchalant attitude on your part. Your doctor likely knows pretty much what is going on in your mind because she has been where you are. Trust her. Many of us have had anxieties about revealing our secret to our healthcare givers. Years ago those fears were well founded. Nowadays, few of us experience difficulties. Even from cis individuals. When we do there are readily available alternatives.
I am now 68 years old. I have been working actively now for 10 years to reach the point I have. A lot of baggage to unpack in various ways. Many things to keep in play to achieve the best possible outcome. You are in a great position to get further along than many of us possibly can in far less time than it has taken me.
Take some deep breaths. Get some help. Gender therapist, if you can. Read of the experiences of others here on Susan's Place. Call on us for advice and encouragement. Dump on us when fears overwhelm. Rant to us when things go wrong.
You have time to do it, one step at a time, methodically, and have a lifetime to reap the reward. The point of no return lies far ahead of you so DON'T PANIC!
Listening,
Stevi