Some babies do teeth early, which can occur as soon as 3 months, according to BabyCenter. The average age for teething is 4 to 7 months, with late developers not teething until 12 months or older.
Teeth begin developing prior to birth, and teething occurs when the teeth break through the gums. It is most common for the bottom front teeth break through first, followed by the top front teeth. Teeth along the sides and back come next. It may take some time for teeth to become straight after emerging. Second molars are the last to appear and might not break through until the child is 3 years old.