I had a similar experience of not being interested in anybody of any gender until my early 20s. I kind of hated all other human beings my age and had no interest in spending time with them. Then, at my first furry convention, when the first person who'd ever expressed interest in me was a gay man, I spent about a week thinking about that. I decided that ruling out half the population for something that felt as arbitrary to me as gender didn't make any sense and that I must be bi. (I was not aware of the term pansexual at that point.)

But I also think I haven't been fully connected to my sexual self even after that. It's hard to explain (though you probably understand to some extent!), but since beginning to transition, I've felt more in touch with myself in numerous ways, including my sexuality. That's part of why I'm feeling motivated to try dating. There's a lot of me that I'd like to get to know better.