My DD6 will be 7 in March. She is in 2nd grade. She skipped K last year and went straight to 1st grade. Yes, she is the youngest in the class. Some kids are 2 yrs older than her but she held her own in class. She did CTY grade 2 SCAT last December and got High Honors award. The principal asked me if we want to accelerate one more grade. My DD is having fun in the class being the top student and grade acceleration will work against her just as Grinity said.
The school plan to do above grade level Math via study island while other kids are doing their Math lessons. She is doing Kumon Math and reading 3 grades above level now.
In the nutshell, I think your DS can go to 2nd may be even 3rd. But it's good to start where the kid is most comfortable especially in the new environment. But HG and PG kids will most often rise up to the challenge.
Good luck!
