Parental controls for 13+ children

In setting up screen time for my daughter (who is 13) I found I was unable to set up a child account for her, and wasn't able to link her account to mine. I had no control over her screentime. Is there a way around this apart from changing her birthdate? I would still like to control what she's on especially during school hours, and a 13 year old doesn't need to be on adult websites either.