If you are holding back just to play lacrosse, you are a fool. Academics is another story. If going from a public school to a private school, you will need the extra year to catch up unless you are a very high achiever in the classroom. Look at all the rockstars from the class of 2018 and 2019, most of them are no longer. The holdback arbitrage is complete. Stopped growing, stopped caring, girlfriends, realizing that there is very little lacrosse life after college, etc. I say play up, if you can compete you will probably play in college. I know about the getting hurt issue, size matters, and if you are within the middle of the bell curve, I would let my son play. He also played football and which is more dangerous playing up in lacrosse or on grade in football?