We have 3 kids. They’ve all developed differently. I think milestones should be looked at more in the general sense. Not actual hard mile markers to make sure you hit.
Our 8-year-old reads better than most middle schoolers, but he can’t tie his shoes. When playing Mario kart he regularly finishes in the bottom 5 out of 12. His 6-year-old brother regularly finishes in the top 3 beating him handily.
One developed mentally and socially quicker than his peers. The other developed coordination quicker than his peers. Both are “ahead” in the somethings and “behind" in others.
Totally normal.