Is your child an asynchronous learner? What does that mean? An asynchronous learner is a student that learns at different level, most obviously grade levels. For example, a third grader might read like a fourth grader, do math like a third grader and write like a second grader. This learning style is common in the gifted and talented population, but typically extremely underserved. Supports might include cross-grade level grouping, subject skipping, grade skipping, ability grouping, and forms of differentiation.
The hard part of advocating for your child is to find an administrator who is willing and/or able to accommodate your student. Often the argument is having younger and older children together. Another argument is that the child may not be mature enough to handle the advanced class. And, lastly what I know is unfortunately common is the ideal of being elitist. "What makes you think your child is so smart and better than the rest?" Administrators do not get much training in programming beyond the confines of the age-grade based system. Also, local policies and budgets force the one-size-fits-all approach. Therefore, your child is likely to just ride have to ride that wave.
Asynchronous learning is easy to support when a school embraces the ideas that children learn at different rates. And, students can have strengths and weaknesses that cross grades and a yearly defined curriculum of what is taught and how long it is taught for. It's amazing to ride those waves of growth and give kids the ah-ha moments of thinking differently to help them understand how to use their unique approaches to learning things that might seem hard.