If her adult teeth are coming in and they aren't pushing the baby teeth out (you'll know because you'll see two teeth where one should be), you'll have to take her to the vet to have them remove the baby teeth so her teeth will not be messed up and she'll have proper tooth alignment.
We had do to this with Seamus AND Kirby because both of them had some puppy teeth that were not falling out and the adult teeth were coming in beside them.
As for the puppy teeth that have fallen out, don't worry about them.
They're just baby teeth and the adult tooth will come soon enough.
It's just like a human baby--they lose a tooth, but the adult one does come in eventually!
Swirly, Squashy, Squishy, Spot, Star, Slash and Rocky
Indy and Myfanwy 
Tilly, Emil, Sonny and Smudge
I've been frosted! 
