Thanks I will do some investigation. The idea of giving them the basics of K appeals to me, as does skipping a lot of the 1st repeat (add ons). My DS is actually tall-average (80%) and sporty 'enough' to hang with slightly older kids...but it was just until recently that I can see his maturity really making leaps that would lead me to see he could handle this.

He is entering K already reading chapter books, doing pretty complex math equations in his head (some multiplying/division, very good with adding/subtracting and reasoning out problems)...I don't even know what they average 2nd grader is supposed to know at the first of school.