How do I change my child’s birth date in family sharing?

If the current birthdate give them an age of less than 13, you will need to contact Apple Support to get it changed: link-> Get Support

Otherwise, you will need to log in to their Apple ID at https://appleid.apple.com and change the birthdate there: link-> Update the birth date associated with your Apple ID - Apple Support

Note the under 13 years old restriction in the end of article below. Link to contact Apple Support at the end of the article.

Apple ID - Update the birth date associated with.  *