If the email address you are using to register has already been registered with another SEGA service, the date of birth registered with that service will be automatically applied.
If the displayed date of birth is incorrect, please contact the support team for the service you are currently using to have your registration information checked and corrected. When contacting them, please clearly state that you would like to correct the registered date of birth, for example: “The date of birth registered to my account is incorrect, and I would like to have it corrected.”
If you are unsure which service you are using, please complete your SEGA Account registration and then contact SEGA Account Support with details of the issue.