Poke, poke, poke -- and the thought springs up that she can't, that her little sister, like her, falls in the category "mad scientist" because the rules of the world are you can give people powers, or you can get powers, but you can't do both. But that doesn't make me happy.
All right, I declare by authorial fiat that trying to give superpowers to a child can turn out very badly. (Or at least, the older sister's source of information says to, which amounts to the same thing. A little flexibility for possible future stories.)
Still, the most that does is keep the little sister from cluttering up the story. I suspect I will have to tie off the thread at the end. It would make a good conclusion to either give her powers or show her granting them.