People's brains tend to continue developing until the mid-20's. Up until then biology dictates that there will be differences in "planning, prioritizing, and making good decisions". People are different, and developmental factors like maturity can vary a lot from person to person but dating after later 20's was just so much better I'd need a compelling reason to go younger. It's really nice to date a reasonable adult, which happens at different ages for different people.
As for high limits, if the attraction is there that's good enough.