I would start by talking to the teacher. What is her impression of you dc? She may have started to notice your child advanced abilities. Then the you could work together with her.
From experience, go with your gut. Don't wait. Kindergarten was very damaging for my ds.
One thing someone told me to say was school is easy right on purpose, so you can learn school- routines, school environment, etc. it is the beginning and the teacher is trying to assess the kids right now.
I'm sure others will give more advice. Keep us posted how things are going!
