Malarky.
There is no such thing as "transgender". It is a made-up concept to cover for someone who has a sick mind and unnatural desires (the Bible is pretty clear about those unnatural affections/desires).
There are a relatively tiny number of folks who are born with a chromosomal issue where they might have some sex traits of both genders - but still, they are at the root, fundamentally one gender or another. But again - this is extremely rare.
This is not one of those cases. This is a case where a girl isn't happy being a girl, so she wants to be treated like a boy. Period.
I am glad this school is sticking to the law.
Why would a woman want to be a man in this day and age. Men are marginalized, castigated, wussified, and dismissed.