The five categories of ages include one month, two to three months, four to five months, six to nine months, and ten to twelve months.

The four categories of the developmental milestones include gross motor, fine motor, language and social/cognitive.

If the infant is not walking at fifteen months, it is essential that the mother bring the infant to the pediatrician for a follow up and further evaluation. These are the type of questions you will encounterĀ a lot but this chart can help you out!