Is there a critical age where kids develop their motor skills?

This is a yes & no: In normal development babies nerves mature enough for the skill to emerge, baby has the requisite nutrition and freedom to move & a skill emerges in a specified sequence.The pattern is head to toe, central to out.If motor nerves were injured, other nerves may come on line for a skill to emerge but may be delayed. Therapy can bring out some but not all skills.

Develoing skills: Most gross motor skills occur during the first 3 years of life. Another set, including both grass and fine motor skills occur when the children reach school age.