There are several of us who have new K-ers here...and I believe we are definitely all relying on the wisdom of the experienced members on here.
My biggest mistake, thus far (there's sure to be more), was assuming that the teacher WOULD just realize ds was ahead by observing his level of work, comments in class, etc. Now I see that his teacher is fielding 20 kids and truly cannot give the one-on-one attention it takes to truly assess a child who is ahead. What they are drawn to, I'm sure, is the child who is lagging behind (or getting into trouble).
If your school has a GT program and/or your state mandates GT identification, you should be able to request an assessment for the GT program.