How to change the birth date of Apple ID account?

Hello my child’s birthday is entered wrong.

If you wish to correct that there are some steps to follow in Apple's support document Update the birth date associated with your Apple ID. Scroll down to the paragraph labelled Change a birth date for a child.

If the steps in the Related Article above didn't work, contact Apple ID Support for assistance.  See the Apple Support articles below for contact information.  

Apple ID - Official Apple Support.   -

Contact Apple for help with Apple ID account security - Apple Support.  *   (Link doesn’t always load)  

Get Support      -    Work through the screens to get a chat option. You may have to pick a slightly different problem.

Apple Support schedule phone call.   -

If necessary, try Twitter

https://twitter.com/AppleSupport.    -          

From the Apple Support article below. 

Without proof of your identity via security questions and other carefully selected criteria, Apple Support can't help you reset a password or perform any other actions on your account. These policies are audited and reviewed on a regular basis.

Security and your Apple ID - Apple Support.      *