A few things I've been thinking following this conversation.

The big one is that as much as Viera kits not having physical gender differences is weird to us, it must be just as weird for them coming into contact with the other races and learning that - by their concept - others' children are born with defined genders and adult body parts. And probably leads to some awkward conversations if another Viera doesn't warn them first.

And then on a personal headcanon note, I think my Viera has a teasing sort of personality and he finds it amusing to deliberately mention how he left the village once he discovered he was a man, and see how the other person reacts once they catch on to the implications.

Though a little less flippantly, I did solve something that was bugging me which is how to get him out of the forest because he didn't want to be a warder, without fully wanting to abandon his culture as well, and I settled on an idea that I quite like - he saw the Echo-granting starshower when he was a kit on the verge of maturing, and so got a sense of being called to leave the forest, but wasn't really sure if he should listen to it so he sort of "made a deal with the forest" that he'd leave if he became a man or stay if he was a woman. So that turned out to confirm that he should leave, and then a few years later he met up with some travellers from Eorzea...

Mostly he doesn't like to talk about this in depth though, so he just goes with the "nah I didn't want to be alone in the wilderness for the rest of my life so I shirked my duties and ran off" thing. Which is also technically true, or at least what he was planning before he had a more significant reason to do so.