When a newborn is born healthy without any disorders the newborns head should be around 13 and 3/4 inches in size.
At one month old the babies head circumference should be 15 inches and by 3 months old the babies head circumference should be around 15 and 1/2 inches in size.
Normally a babies head circumference grows at least 1/2 inch per month until around age 3 and then the head stops growing as fast.
But as the baby gets older and older the head should continue to grow more and more a little at a time as the toddler grows into a child, teen and adult.
Once the child reaches adult age their head stops growing but their face can change in appearance as the person ages.