From what I have heard from almost all staff is that maturity is one of the biggest. Age comes after that. You can not judge a person by their age or sterotype by age. That's called being ageist.
Gwism has said that not only do you have to read the rules, you have to embrace them, you have to understand them. Yes, knowing the rules is important, but putting them to use and understanding the nuances of each rule can be extremely useful. I know you state this in part here, just wanted to elaborate.