Hi Robert,
Thank you for visiting the Disney Parks Moms Panel with your question. I am happy to help you with your Disney planning question!
In order to change the age of children in your My Disney Experience account, first you will need to log into your
My Disney Experience account. Next, under the "My Disney Experience" tab, under "My Account," choose "My Family & Friends List." Then, find the child whose age you want to change and click on "Update." This should give you the option to change that child's age. You do need to be the person who manages that child's plans in order to do this, and that should be listed on your Family & Friends list. For instance, I manage my daughter's account and was able to get in to change her age. We recently took a trip with another family and linked our My Disney Experience accounts with that family. I can see the children from that family, but their mother is listed as managing their plans, so I cannot change their ages.
If you run into further issues while trying to change the age of a child in your My Disney Experience account, I suggest that you call the Disney internet help desk at 407-939-7765. A cast member there should be able to help you with your specific issue.
I hope that this information is helpful for you, Robert! Please do let us know if you have any further questions.