It was a month before my 22nd birthday when I realised I was, well, am transgender. If what my family members say about me has any truth to it, I exhibited signs of not conforming to my assigned gender for a lot longer than that (around as young as five). When I came out to them, it seemed like everyone else already knew. I guess I'm a bit slow on the uptake when it comes to things closer to home. It's not an unusual thing for me, at any rate, just wish I had woken up to myself a bit sooner, might've saved some wallowing. Perhaps it was for the best though, by realising at a later age I saved myself years of gender related depression. I already had depression related to other things, but hey, it could've been worse.
That I realised at all is good enough for me. Don't think I would've enjoyed the life I would have lived if I continued to be "blissfully" unaware. Not sure it would've lasted much longer either. Anywho, enough about me. This was an interesting thread to read, thanks for posing the question.