Is it all-day kindergarten? Half-day would be ideal because you could work on social part-time.

I would NOT suggest waiting. Having them in young when they are bright is like getting a "free skip." I have two DYS that are naturally young for grade and I did not realize at the time just how lucky we were. DYS DS6 is having a very tough time in 1st grade because everything is so easy. If we had held back, it would be even worse.