My first advice would be, "don't cross the bridge until you come to it." You've got 2 more good years before you need to worry about a bad year, right?
It's also not clear to me why they're suggesting a full 2-year grade skip to get her Algebra 1, when the middle school does do math acceleration. Or are they saying, "as long as she's ready for Algebra 1, which is likely to be the sticking point, may as well accelerate in everything"?
I will say that a 9th grader taking Algebra 1 with 9th graders is not going to be in a high-performing classroom. That schedule won't get you Calculus before graduation in most schools. (Our district is Algebra 1, Algebra 2, Geometry, Trig / Math Analysis, then Calc. So if you don't take Algebra 1 in 8th, you don't get Calc in 12th.)
I'd look at the other stuff offered in 7th / 8th, too, and whether they're required or helpful to getting into the higher-performing classes in high school.
