Change the birthdate on my account

If you accidentally set his birth year to 2025, Microsoft now thinks U R 0 years old.
When an account is classified as a child account, Microsoft locks the ability to edit the birthdate for safety reasons.

So the system is behaving exactly as designed.

✅ What options does he have?

1) Add a Parent/Guardian account and give consent

This is the fastest and most reliable solution.

You need an adult Microsoft account (can be a new one).

 Steps:

1. Go to login.live.com

Sign in with the child account

When asked for consent, choose “I’m a parent or guardian”

Sign in with an adult account

Complete the consent process

Go to: https://account.live.com/mykids.aspx (account.live.com in Bing)

Select the child account

Click Edit this child's personal info

Correct the birthdate

This unlocks the profile.

2) If U R already part of a Microsoft Family

If your account is already under a family group:

The adult account goes to account.live.com/mykids.aspx

Selects the child

Edits the birthdate

3) If Microsoft thinks U R a child even though U R not

This happens when the wrong year is typed.

If the profile page shows the birthdate but cannot be edited, it means the account is flagged as a child.

Solution:
follow option #1 (add a parent account).

4) Contact Microsoft Support

If the system refuses to unlock the profile even after adding a parent account, Microsoft Support can manually fix it.

This is rare but possible.

*** The quickest fix

Create a new adult Microsoft account → use it as a parent → give consent → edit the child’s birthdate.

Total time: 2–3 minutes.If your friend accidentally set his birth year to 2025, Microsoft now thinks he is 0 years old.

When an account is classified as a child account, Microsoft locks the ability to edit the birthdate for safety reasons.

So the system is behaving exactly as designed.