According to pediatricians, babies should be lifting their heads when they’re around 4 months old and rolling over by 5 or 6 months old. They should be taking their first steps around 9 to 12 months and walking unassisted between 14 and 15 months, probably no later than 18 months.
Most parents know their children should be feeding themselves by a certain age, talking by a certain age, and hitting the right height and weight markers by certain ages.