It’s normal to occasionally worry about whether your toddler is developing as he should, or to wonder if there are any milestones all children are supposed to hit at 21 months old. Try to remember that each child develops at his own pace and on his own timeline. Although it may be easier said than done, try not to compare your little one’s progress to other children's achievements. This goes for comparisons between siblings, too; try not to compare your 21-month-old’s development to that of your older child at the same age.
If you are worried about any aspect of your little one’s development, talk to your child’s healthcare provider, who can provide reassurance and recommend any next steps that are needed.