Really cool story, and I think that even if this kid is too young to be making this decision right now, you've got to respect not only their confidence and strength, but also the support system and family that seems unfaltering. I really respect this kid, a lot of adults can't accomplish the great feat that she's pulling off by being confident enough to go back to school and continue with a normal life.
I remember very distinctly in kindergarten how we were learning everyone's names and our teacher took pictures of all of us on the first day of school and a few days later we had to classify those pictures into groups to see what people had in common (favorite color, sport, animal, ect) and also gender. My favorite color was green, I played baseball and basketball, my favorite animal was a hippo. I fit into the boy side of the chart, and I remember there was this one kid who insisted that I must be a boy. The teacher eventually convinced her otherwise, but there's always been that slight question in my mind about my gender identity. Since adolescence I've calmed down a little bit, but it's still something that I think about when I'm picking out clothes and my sister is trying on dresses and I'm looking at t-shirts and jeans.
I guess the moral of my story is that I think for some people, it's easy, they're born what they feel. For others, it's opposite, and their body doesn't match their brains. I think that I'm somewhere in the middle, I don't mind who I am, but sometimes I'd like to be able to try out the other. Thanks for reading this rant, sometimes I go off on tangents that are unrelated, but good to help clear out my mind.