I think it makes sense since 6th graders can't play in middle school. There is a huge difference between 6th and 8th graders physically. However, I see your point on the U13/U15 thing. Having two teams grade based would make more sense, but I don't know if you have enough players to do that. Of course, exceptional 7th graders should be allowed to play on the 8th grade team if they are able. Since it ;is outside of school play, I don't see why a talented 6th grader couldn't play on a 7th grade team.
