Age change
How can I change the age of my son if he is over 13?
Question marked as
If his birth date is currently set for an age under 13 and you want to change it to over 13, you will need to contact Apple Support. See the following from Update the birth date associated with your Apple ID - Apple Support
If you need to change the birth date for a child, contact Apple Support.
If it is currently over 13 and you want to change it to another age that is also over 13, see the "Edit your birth date" section of that same support article.