Developmental milestones are an important part of your child's development. Please note that these are just guidelines for development, and not all kids will progress through each stage and area in the time framed described.
"While we teach our children all about life, Our children teach us what life is all about"
Kay Redfield Jamison
Go with your gut, if you sense something is not right, it's better to check it out, rather than "wait and see".