Hi Autumn!!
First of all, thank you very much for sharing your thoughts and experience!! It was very brave of you!
I am 36 just like you and also married to a woman.
It is indeed very hard for them to deal with all about it. But the truth is that the only possibility for everything to work out well is that if she "transitions" together with you. Just like it is a huge step for you, you have to understand that it is also for her. She really needs time to understand, to adapt, to see you are still you and to realize if she can allow herself to love and be married to a woman.
I think it is of the utmost importance to understand that you both need to transition together; you need to include her on every step you take, every decision, every doubt and every certainty. Work first your issues inside your head (see a gender specialist therapist if you can) and then when it is a little more clear for you include her on the issues (please don't assume they are YOUR issues. You are married and you love her! So your issues are also her issues).
I will share what happened to me and my wife about our transition hoping that maybe any of my experience can help you somehow.
With my wife, even though she declared, since the beginning, she is not lesbian and she will not be able to live with me as a woman, we are doing fine so far. The more important thing I guess is for her to understand what is going on with you and why.
For me it started just like that. I once told her I liked to dress up as a woman (she also freaked out and thought I was gay and everything was lost...), but I patiently and many many times explained her I was the same person, I was not interested in men, that I love her and this would never change.
I explained I dressed up because I've always felt like a woman inside, but this is the only way I could express who I really am. A few months later, I told her I was going to started epilating all my body hair. She hated it (today she likes it), then we talked about facial hair; my hair was growing and started to use more and more female accessories (in truth I've always used them).
One day she asked me: "do you really want to be a woman?" I've answered "I don't
wanna be a woman. I
AM a woman, but as I was born male, just now I could realized it."
I also told her if it weren't for her this would have happened already much earlier, but I just couldn't stand it anymore. But as I love her more than everything, I would not live as a woman if she didn't accept it, because she is my priority.
Months later we talked about my intention to start HRT. For her it was like announcing I had cancer. I reinforced all the things I said before, all the love I feel for her, and reassured her that I really needed it.
She thought about breaking up, but I asked her to let some time pass, that everything would change so slowly and I needed her to watch the changes and she if she could adapt to them. And postpone any decision about ending our marriage until she is absolutely sure she couldn't live with my changes. I again reassured her I would not live as a woman until she decided she was ok with that, or until we really separate.
She agreed... almost 8 months have passed since then and it looks like everything we went through reinforced our love and our care for each other. I have absolutely no idea about our future, about what will happen. But so far I still express myself as a man but I feel like the most happy woman in the world living my own fairytale.

Well I really hope it helps you somehow...
Best wishes!!