I agree with you futbol....good points. Size matters. Just because you have U-18/varsity skills, doesn't mean you belong in a U-18/varsity game when you are 12 years old.
Would you agree with me that the argument from the girl's side is a little different from the boy's side?
#1 - The size differential between an 8th grade girl and a senior in HS is not as significant.
#2 - Girls really appreciate the social aspect of the sport and feel connected to the high school. JV (middle school) girls love riding the bus and hanging out with the older players, some of which are their siblings.