While it can be seen as a form of discrimination, I personally don’t think it’s an issue if you set a relatively low age, such as maybe 20 or 30 days. In many games I’ve been a part of, especially in the RP community, account age requirements are almost a given due to the exploiter problem.
At the same time though, if your game is this vulnerable to exploits, maybe you should look at your scripts and think about restructuring how your game works. Take a look here to help understand how exactly an exploiter could gain unauthorized access to certain parts of your game, and how you can script to defend against it.