In all youth recreation sports, you play against kids within a year or so older or younger (there would be too many age groups if you went by numerical age exactly). In HS and College you could play against players around 3 years or so older or younger. What is the question here - that maybe when a kid is in the 7th or 8th grade, and plays club lacrosse, he may have to play against a kid a year or so older or younger, like he has been his entire life? This is a loser debate. Lacrosse players care zero about this mundane issue, but I guess if you incessantly droll on about something long enough, it could become a real issue in your own mind.