Balsamicpearls
Your child will be female for the rest of her life. Nothing can ever change that. No amount of surgery, lifelong hormones can make her a boy. And I know, you are not considering that, at all. But it's worth noting.
Males and females transition for different reasons. I don't think it's much of a surprise to anyone that girls see boys as having fewer limitations, more agency and less disadvantage and want that for themselves.
Most children go through wanting the role of the opposite sex. Of course. It's only society that tells them that's not entirely natural and defines things as 'opposite' in the first place.
If you do nothing more, I urge you to watch this programme, broadcast last week by the BBC. The children in it are exactly the same age as your daughter.
It comprehensively highlights that by the age of seven, girls and boys are thoroughly entrenched in their society enforced gender roles.
Unasked for roles. Roles that are very difficult to break out of, should one even be consciously aware of them. Which hardly anyone is.
Watch the total shock from some of the adults in the programme, who would have sworn blind that they do not enforce gender stereotypes, when they are filmed doing exactly that.
www.bbc.co.uk/mediacentre/proginfo/2017/33/no-more-boys-and-girls