But then, since it is a promotion instead of acceleration, you may find yourself back in the same position very quickly, as soon as your child decided the pace of 7th grade math too slow. So perhaps it is more beneficial to spend the time to develop an enrichment plan instead of arguing with the district every year?
I had to quote this because this is the universal truth for most kids gifted in math in a schooling situation (as opposed to homeschooling). Subject acceleration of 1 year is not adequate for any child that I have known who is gifted in math. I encourage you to get a hold of the 7th grade textbook that your school district uses (borrow one from the math department or buy a cheap used one on the internet) and see exactly how much more advanced the next year's curriculum is compared to the current one. That would give you an idea of what is in store. What I suggest is that while you advocate for your daughter's skip, simultaneously look into how you can provide enrichment in math, independent of the school, and try to bring back her love of math. In most cases, kids who are skipped by a grade or two in math find the content within their grasp.
Some ideas for enrichment so that it brings back her interest in math are: Math Circles, Math Festivals for girls (Julia Robinson is excellent), low pressure and fun math competitions like Math Kangaroo, youtube channels that talk about fun math concepts in a way that engages kids: ViHart, NumberPhile etc.
Good luck.
