Well, you could talk to this therapist and find out how much experience she actually has. If you're not sure, this is a question you ought to ask directly. Ask a lot of questions. How many trans people has she worked with, how many is she working with now, how many has she taken to/through transition, how many FTMs, stuff like that. If she's not the one you want, you can ask if she can recommend a particular practitioner. If you already have some names, it would be interesting to see what kind of referral she gives you.
If you don't ask specific questions, you could wind up with someone who means well but can't serve you well--maybe she knows a little and thinks she can get up to speed. Nope, you don't want to work with someone like that.
I would strongly advise you to see someone who has extensive experience with trans issues, someone who advertises himself or herself as such. It takes a lot of work for the non-specialist to get up to speed, and some practitioners might underestimate the difficulty and delicacy of working with a trans person. Someone like that might also miss a lot of things or might be too quick to agree to an HRT letter. It might sound great to get the letter sooner, but you need to be ready on the inside, and the person you see needs to be able to accurately gauge your readiness. Sometimes we lie to ourselves and others. Sometimes we miss things in ourselves. Why not let a true expert guide you through?
If you want to go with an informed consent model, then that's your lookout. I'm just saying that if you are going to go through therapy--and if you plan to take it seriously and if you have any issues to work through--then you probably shouldn't jump into HRT too quickly. Especially if you're going on T, which has dramatic and irreversible effects.
That's only my take on it, but I suspect that lots of other people here will agree.