the wrong date of birth is on my account. I am an adult and not a child..

If the account is treated as a child account, the birth date cannot be edited directly from the profile. The fix depends on whether the account already has parental consent.

1. First, check the profile at https://account.microsoft.com/profile/edit-profile-information.
2. If the profile opens but the birth date cannot be edited, use the adult Microsoft account that originally gave consent:
   • Sign in to Manage child accounts at https://account.live.com/mykids.aspx
   • Select Edit this child's personal info
   • Update the date of birth
3. If signing in shows "Parent or guardian consent is required for this account", start a consent request:
   • Sign in to https://login.live.com
   • Select I'm a parent or guardian
   • Sign in with any adult personal Microsoft account, or create a new adult account
   • Select Yes, I agree on the consent form
   • Select Family Safety to complete
   • Go to https://account.live.com/mykids.aspx
   • For the account name, select Edit this child's personal info and follow the prompts

Important details:

• A child account cannot remove its own consent or correct its own birth date while it is still classified as underage.
• The adult giving consent must be at least 18 years old, except in Canada where the adult must be at least 19.
• If the needed adult account cannot be accessed, try recovering that adult account. If sign-in problems continue, use the sign-in helper or Contact Support. Support agents cannot directly change account details.

References:

• How to change a birth date on a Microsoft account
• Managing parental consent