Can’t access email account ; change of birth year to current year changed to child account

I recently changed the birth year for my newly created email (for security reasons), not realizing it would change my account to a child's account.  Now I can't access the account without signing into a parent's account and submitting credit card information.  How can I access my account without the charge?  If the rules are so strict to enforce security for a child's account, why was I able to change the birth year, causing the email to change from adult to child?  Plus, I don't think it's fair to charge a $.50 fee when the account was originally created as an adult account.  I only changed the year after I was unable to keep the correct birth year from being displayed.