I'm not sure how to answer. I was fifty-nine when I started HRT and I had spent the better part of a year researching the risks and possible outcomes, including FFS, not including FFS. Gobs of BS looking for another way out. Finally, I couldn't find one.
At twenty-four a girlfriend dumped me because I was too feminine, so I thought maybe I was gay. Well that didn't work out very well so I tried being artistic, acting, stagecraft, anything that would allow me to play with color, style, and form. Turns out I wasn't really good enough and finally accepted that reality. Then some of my friends began getting sick. I've talked about this before, but HIV/AIDS took a number of people that I love. That pushed me down the rabbit hole of denial and refusal to consider anything relating to gender or sexual identity for a very long time.
So I embraced alcoholism and drug addiction with increasing intensity. Got married and began ruining my life and the lives of anyone who cared for me. At thirty-five I found AA and sobered up. Last month I celebrated twenty-five years clean. Without sobriety I could have never had the clarity to finally and belatedly become me.
Well yadda, yadda, yadda time passed I got married again and my new wife asked me directly if I was trans. I was shocked! I assured her I was not - so stupid. Screwed up her life and wasted another nine years living inauthentically. Finally I was pretty much forced to face the truth or wither away. Times had changed, I live in trans friendly Seattle and I could no longer imagine living my life as it was. I began to seek the authentic me. I think I have found her, and I love her. This is the first time in my life I can say that.
So when did I start transitioning? I dunno, a few years or perhaps decades. It has taken a lifetime of struggle, changing society, changing attitudes for me to embrace authenticity. But living an authentic future life, free from the half truths and denial; real; filled with opportunity and in the company of wonderful, amazing people is a dream come true for me.
Ah well short question - long answer - sorry

Julie