L.O.
My oldest daughter was a stutterer. When she was in kindergarten we talked to her teacher about it. She said we shouldn't worry about it unless she hadn't grown out of it by the time she was around seven, then she should see a speech therapist.
She did eventually grow out of doing it and to hear her talk now you would never know that she ever stuttered. What we did to help her was when she started "I,I,I,I" we would have her stop and speak slowly. This seemed to help her brain catch up with her mouth.
Good Luck!