Active cookie — valid .ROBLOSECURITY, not expired
Account 13+ — birthdate can only go downward
No cooldown — no birthdate change in last 7 days
No Account PIN — PIN-locked accounts can't change birthdate
No parent link — parent email blocks age modification
No 2FA — two-factor must be disabled
How to read failures: birthdate fails but email/phone succeed → PIN or parent link. Everything fails → the cookie is expired.