I'm sorry about the issue. Another possibility is if she download / install another app that requires Facetime, like FaceNow app:
If you'd like to, you can enable parental controls by going to Settings -> General -> Restrictions, and Enable Restrictions, then turn off Facetime. Full information about Restrictions (parental controls):
Do you have any further question? Please reply at the box below. Thank you.
That's the only two ways I could think of, touching setting or downloading app. Did you do the iOS software update (version 9) recently? Is Restrictions still showing ON and Installing App option is not allowed now? Thank you.
No, it is not a reason, and there is no delay for facetime activation notice. Thank you.