X had thought that we were outside the hall when he tried to follow the moves. When he turned around and saw us looking at him, he became self conscious and ran away shyly.
As X grew older, he became more and more self-conscious to the point of being shy. That was unlike Z.
However, when he warmed up, he was the mega social butterfly. He had no qualms about playing with the older boys from the martial arts class. Those boys were 8-10 years old. You would see a 2.5 year old roaring and playing catching with the older boys.