You’re right, the difference being a few weeks is silly. There should be a tier system instead. Like 15-, 16-17, 18-20, 21-24. If you’re an old fart, you can only date over 25. If you’re within one of the tiers, you can date within the same tier and maintain any relationship that was started when you were previously in the same tier. Something like that, but with a little more polish.