Before I was even referred to an Endocrynologist I had to see a psychiatrist, but I think a psychologist or gender therapist is much the same. I would imagine he would want you to do the same. My experience is everyone's quite cautious (which is good) to make sure we're making the 'right' decision. And so my Endocrynologist awaited a letter from my Psychiatrist containing a diagnosis of Gender Dysphoria.
A question to ask, at least if your MtF, is around your blood work. There is a specific test they should be conducting around coagulation. I then had a specific test which uncovered something called Factor V Leiden mutation, a genetic predisposition to clotting. There's a protein in my blood that doesn't switch off my clotting mechanism within the blood. And so with eostrogen increasing the risk of blood clots, this further increases the risk.
I would just suggest to ensure you get all your bloods check including anything that would crease your risks.