Do that to put your mind at rest.
But for heavens sake don't ever allow yourself to feel that you have failed as a mother because there are things your ds cannot do!!! Being a success as a mother is about helping and supporting and being proud of your lo within the framework of what they can do.
Ds at 8 cannot hold a pen properly and until recently struggled with reading the simplest sentence (has suddenly come on leaps and bounds with his reading but will probably always have difficulties with motor skills).
As a researching academic, who was myself unusually advanced as a child, I was not perhaps prepared for this. But I certainly don't think I have failed him in any way, and I am just as proud of him as if he were top of the class. And more to the point, he is proud and happy of what he can do (though that took a bit of working on).
Come to think of it, dd can't walk half the time, but that doesn't mean I have failed her either. We all get handed different lives, different abilities by fate; the important thing is what you make of what you've got.
Also, btw, kids keep being taken out of class for different reasons, and moving around in groups- it won't stigmatise him.