Same here, found it with our 36 month old shortly after her second birthday (i.e. about 9 months ago). Why it happened and how it manifests itself are a bit different, but developmental delays and "exceptional children" as they sometimes get called... the process for getting help and support is all the same.

The hard part for us was feeling like the world would leave her behind. Almost as difficult was all the talk / meetings / screenings it took to get her into programs that could help - such an ordeal, so many hoops to jump through. But starting at three years old, i.e. just a few weeks ago, we started doing a preschool program with specialist teachers who focus on early childhood intervention to help catch kids up so they can be main-streamed into the public school system immediately. Now our daughter is exploding with new words and skills. Her issues aren't motor, which sounds like that may be the case for you. But regardless, start those conversations with your school district and pediatrician now.

Don't panic, there's help, and great support out there in your community. Just focus on getting your kid the help they need, and understand it's a long road. He may lag behind peers for several years, but he can catch up, and he does know you love him.