haven't read any of the other replies but I was a MASSIVE tomboy at that age, and until I was about 11 or so.
I understand why you're worried and want to say please don't.
When I was young, for years, I begged my mother to let me have boys' haircuts, I wore only shorts and jeans, I read only football comics (rather than anything girly), I HATED dresses, I HATED girls, played only with boys, etc.
Once on holiday in Cornwall an old fisherman called me 'boy' (I was about seven or eight) and it made my summer!
I ran wild in the fields in the school holidays, went off on my bike all day long, and hated books I was meant to like like Ballet Girls, or whatever it was called, and preferred those boys' adventure books instead - Lion Adventure etc.
Now I am married with three children and honestly you would be amazed if you knew me then and met me now. I still think I'm quite no-nonsense and ungirly - for example I loathe cupcakes and find beauty articles very boring and a hen party is my idea of hell and I hate girls' nights out - but I think I'm pretty attractive, I've got a very handsome, funny and clever husband, and have conventionally feminine and attractive looks. (that sounds wanky but I just want to show I'm different now to how I was then).
Don't worry about her x