Any parents?

I was wondering if there are any other parents of small children on here. My son, 5 years old, is (in some instances) very much like me. He has more impulsivity than I had his age (and he has more hyperactivity as well, even if it's not as big a part as concentration and impulsivity issues). He is also very bright, and started reading at four years old. I suspect that him being bright outweighs/hides a lot of the issues described. Right now (in preschool), he gets by pretty well, and I suspect that, were he assessed right now, he would possibly not reach the criterias (or having enough problems) to get a diagnosis. I'm unsure how to go about this. On the one hand I want him to get the support he needs in a timely manner, and not get a total chock when he starts regular school, but on the other hand I don't want him to go through unnecessary assessments.