How do I change Apple ID from adult to child

Hey there, usavia!

Thanks so much for using Apple Support Communities.

We understand wanting to make sure that all of your Apple ID information is up to date with the most accurate info possible. It sounds like you'll want to follow the steps in this article: Update the birth date associated with your Apple ID - Apple Support

On that page you'll find the steps to update the birth date associated with that Apple ID. We do want to note that if you change the birth date to one below the age of 13 years old, you won't be able to edit it after the fact. The article we linked has more information on that as well.

We hope this does the trick for you!

Cheers.