What is their reasoning? BTDT, we had two years of starting off the year with them asking us strongly to keep DD11 in her normal grade and be "enriched" in math despite everyone being on board in the spring. Same type of message for DDs friend who was doing the same thing. Finally after 2 yrs of being accelerated a grade in math, we got support. It took this long despite getting above a 95 average. The school started us on this path but then would back pedal at any roadblock.
My advice is to stick to your guns if you think it is the right thing to do. I was a broken record saying I think her grades speak for themselves, she should be treated like any other student in XX grade math and be advanced accordingly. Sticking to our guns and following DDs lead. This has resulted in a great math year with a math class at the GT magnet. She's learned many new concepts (while not super difficult they were new and at a faster pace). In addition, I believe the whole process has added to her independence wrt to telling the teachers what she needs on her own. They take it better coming from her.
Good Luck
