Legally, haven't started. Not super important to me, it's pretty far down the dysphoria tier list.
Physically, (I know you didn't ask but I care) I realized that body hair and balding were the main triggers for my dysphoria, so after talking to my wife about it, I got a prescription for finastride and a laser hair removal thingy. Using those the last week or so has been super gender affirming (and itchy).
Emotionally, this has been really hard on my wife. She doesn't perform gender, and the only connection she feels to her gender is her sex, so she feels that her womanhood is threatened by me fully coming out. If I am a woman because I feel like a woman, then what does that make her, when she doesn't have a specific attachment to her gender? The newest compromise is that I can be as fem as I want, but I'm still her husband, not her wife. I'm trying to tell her that if she wants to be a woman, even in a "don't let go of what I have" way, that's totally valid, but if she just drops the gender completely and goes they/them or xe/xer, that's also totally valid. We are going to make this work somehow.
Socially, my sister is throwing a little superb owl party this weekend, so most of my family (and no one else) will be at this party, so it's time to rip the 30 year old bandaid off and come out. Since I'm still in negotiations with the wife, it'll be phrased "struggling with gender dysphoria and being more fem helps so much" instead of a full "My name is Amber, please refer to me with she/her pronouns." I'm expecting a lot of acceptance and questions.
Spiritually (I know you didn't ask but I care) I found a verse that is very specifically trans affirming. No idea how I missed it every time I read Isaiah. "For thus says the Lord: “To the eunuchs who keep My Sabbaths, And choose what pleases Me, And hold fast My covenant, Even to them I will give in My house And within My walls a place and a name Better than that of sons and daughters; I will give them an everlasting name That shall not be cut off." Isaiah 56:4-5 NKJV. I've been trying to find a way to reconcile my faith with my gender identity forever, so reframing eunuchs as trans people and then doing a study has brought me much peace. My wife is still struggling to reconcile being bi with her faith. She didn't have to worry about it as she could just marry a guy and ignore the bi, but she did the most bi thing possible and married a closeted transfem, so now she has to confront it. It's a process, we'll see where we end up.
Sorry this is long winded, but your question gave me the framework needed to actually put everything down into words, so thank you for that.