this is hard i was so young too at the time didn't even know they existed i was almost 10.

if she is in denial it will be tough for her to accept but a little teesing from other girls if it seept through her clothing will open her eyes.
i agree with the own washing idea too. tough love my mum used to call that sort of thing. she will have to do her own washing sooner or later anyway.

and also maybe get her one of those teenage self help books. there are heaps around, facts of life books that help teach teens to be healthy individals but in a way they understand, any parent to a child is daggy and wouldn't understand in their eyes. i was looking at some in a book shop not too long ago, there was heaps about periods and cycles sex and boys and all sorts of things.

Good luck hope it works out