I realize that the percentiles don't mean my kid can do 6th grade math - heck, I'm not sure she can do what I term 4th grade math. However, I do think most folks in the US would say that an 11th grader or below in Calc BC would be two years advanced. I would consider "normal" to be Calc AB/Calc I as a senior.

What is K math these days? If the 6th grade math my kid will do next year isn't even Pre-Algebra, what the heck are they learning all those years in elementary?