Account Integrity Score, which is a system which could be verified by a number of factors is a better system than AccountAge.
Lets say a bot attempts to attack your game with 0 save data, 0 RAP, 0 Friends etc; Account Integrity of that account is zero
Of course, you would have to create this system yourself, but the concept is there.
Relying on just account age is weak as many of these bots rely on pre-existing accounts due to the fact that you now need a captcha to create new accounts