alt Hacker NewsI had the UK Age verification popup today. It verified immediately based on the age of my Apple account, I didn't have to take any further action. I am much younger than the OP, and probably than their Apple account. I am surprised that this didn't happen for them.
The OP states they've migrated. That might mean that the field on their account database entry might be related to that move. The account is older, but when moving countries I've had to do weird dances to get my Google accounts to accept the new locale, and wouldn't be surprised if their computed account age coincides with me having done that change.