College kids have the same problems being responsible at 20 as they do as 18 year olds. I was guilty of that. Not getting the older is better thing either. In football players are auto redshirted so they can gain 30-50 pounds in the weight room at many positions. It is also a sport that allows 85 scholarships for 11 spots at a time on the field. You can fully scholarship 5 QBs. In basketball they don't redshirt guys. In soccer, swimming, baseball, etc they don't. Going back in lacrosse to the 1990s or 1980s did the top players then struggle as 18 year old freshmen against older players? I don't think so. Once you are 18-19 you are good enough or you are not. If you are a middle school kid playing against kids a year or two younger, there just isn't any way to see that as an outlier. I'd feel differently if I saw a 14 year old 2019 kid tearing it up on a 2018 or 2017 team. But I've never seen that at a club lacrosse event.
Did all of these lacrosse coaches read Gulliver's Travels and get carried away? A 16 year old 6'3 9th grader probably is not going to grow to 10 feet tall.