Same here, we went into AoPS pre-algebra in 4th. The school said they would accommodate but it never panned out. Just a few here smarty pants do these work sheets type of things. We also had a high school student tutor a night or two a week to help. In 5th we switched to a private school.

Being ahead of the curve has its problems too unless you surround yourself with others who are ahead also. JMO. I say that because we did a lot of competition math.