Dottie is right about all of that. "Deceleration" can be as simple as "I'm not taking a math class this year," or afterschooling something like Discrete mathematics. I didn't take a math course my senior year in high school. I'd already met the graduation requirements, and as long as you have enough credits and you've taken what the state says you must... you can do whatever you want. (Power to the people!! er, sorry. heehee...)
Back on track. You have to do what your heart tells you is right; sometimes that's a slim margin.
We are also planning to delay Calc by placing AP stats before the calculus sequence (thus delaying DiffyQ to college), and holding off any firm decisions regarding just "where" calculus happens. It could be dual enrollment credit, could be AP class via the high school.
DD's a similar case to her son, it sounds. That is, her READING skills are elevated too, so a full-grade skip was no problem at all. (The real problems come about when that isn't enough.... but that's another story.)
I'd be very hesitant to accelerate a child without literacy skills at least a little beyond the destination grade. Writing skill weaknesses are one thing (that's pretty common), but reading skills can create global problems in grade 4 and up.
