Callaway,
How do 7th graders get on a HS JV program? Around here the middle schools are separate from the HS and there's no middle school ball except at a very few private schools.
The frosh/soph team is almost always entirely freshman and only a very few freshman make JV. I've never seen a 7th grader that would have had much chance to make one of our JV teams even if they were allowed to, although we do have the ocassional freshman make Varsity who is usually equivalent to a good JV player. This year we did have one 14yo freshman make varsity who was a solid varsity player, but he looked more mature than most of the varsity players and was one of the bigger players on the team.