For me, my mother told me she knew I was attracted to women since I was 3 or 4 years old because of the way I reacted to lady wrestlers on the television.
My orientation was never a mystery, but learning I was a lesbian was connected to understanding my gender. I did have a brief relationship involving a man after transition, but I broke it off after I realized that I did not like him, or men in general, the way I liked women.