who doesn’t want to be 100% a man or 100% a woman.

I'd go further and avoid any kind of "want to be" wording in explanations to people who can be really doubtful. Gender is who you are, not who you want to be. If you tell them "I want to be ", they might form some kind of "attack helicopter" opinion/joke. but if you tell them "I'm on the inside" or "despite my body, I'm actually ", that leaves a lot less room for wrong interpretations.

"Someone who's gender identity neither aligns completely with man or woman" would be my rewording, in this case.

Is there a way to mix in the old concept of Tomboy into the conversation since that's something older folks would maybe understand?

Sounds pretty solid. I'll try it when it next comes up!

ok wait, i know what nb is but think somethings going over my head here haha. i’m just a bit confused- can you just elaborate on what you mean by “you could pick where it sat each day”? or is that just meant to be part of it being a simplified version of nb?