The fact is that all kids are still learning how to sit still and how not to interrupt in KG. Your DD won't be the only one interrupting the teacher. My DS did that all year long last year, but he finally calm down in 1st. Kids in 1st however can follow rules better and they can sit still for a longer period of time.
There is also a factor that you have been HSing for a little while and she is not adjusting to the new environment. There are a lot more freedom when she is HS'd versus in school.
Maybe just talk to her and give her a little time?
