Parental Control Age Limit?

I have two young children with access to various 'i' devices that I originally gave them access to under my Apple ID. Due to rediculous amounts of screen times that they both seem to accumulate I've decided to set them up with their own ID's so I can utilise the Family Sharing and Parental Control functions (Oh, there will be some complaining, lol). My son is 11 and it was all easy. My daughter is 13 (going on 16) and I still have her as a child under my Family Sharing so it's all good for now; BUT;

My question is; does the Family Sharing recognise age after 13 and automatically turn off parental controls? If so, at what age does this happen? I'd be concerned if it was before the childs 18th birthday (I know, I'm evil :-))

Cheers

Cinful