Last year, K teacher got the impression I was "pushing" DS. She was nice, but misinterpreted his perfectionism as a reaction to pushing rather than reaction to always knowing all the answers in school.
Did our kids have the same teacher last year? I found myself in exactly the same situation last fall and that was the main reason we got our son tested. Fortunately the copy of the test results took care of the "pushing" part and him "learning to please me"
At this point I would probably write down what he likes and doesn't like about school/subjects, throw in perfectionism as well. Give her a week or two and set up a meeting with her to see how the transition is going and to give her heads up on all the things he can already do.