Catherine,
I started a kind of stealth transition, changing little things one at a time, trying to "femme up" without raising to many flags. That was probably about 10 years ago. My deliberate transition started around July of last year, when I made my first appointment to solicit a prescription for HRT. From July, I started taking estradiol and spironolactone, changed my name in January of this year, came out to my family in April, and then out to everyone at work and on social media as of May.
So in a sense it took less than a year, or maybe it took almost 10 years. I tend to count from the point of my decision. All of the vacillating before that was probably more like experimenting than transitioning.
Erin