Okay, it's been said before, but it was as soon as I discovered I was a woman (so almost 2 years ago). However, there's more to it for me! I can remember having lesbian fantasies as far back as middle school (where I was a woman in the dreams). In hindsight, it's incredibly funny that I thought nothing of that, and wouldn't realize I was a woman for over a decade afterwards. I just thought it was a fetish thing, and honestly it made me feel kinda guilty about myself. Later on, I'd take it even further by watching POV porn from a woman's perspective (which I also considered a fetish thing). It's obvious now why I enjoyed that POV more, though I stopped watching porn a long time ago now (before I transitioned, even).

As for discovering I was a lesbian specifically, I was pretty confident of that as soon as I started transitioning, though I did have a little bi curiosity with a trans man I met a few months after starting HRT. I've since reflected on the situation, and currently define myself as a lesbian.

Also, before my realization, there was some amount of time (around a few years) where I has this kind of resentment that I "couldn't be a lesbian". Somehow, despite not recognizing I was trans—or even understanding what it meant, since I had never been taught anything about what it means to be trans—I still resonated with lesbians. Which obviously, in hindsight, is funny now given that I am a lesbian!