Many parents question whether or not this means that their baby is teething, but a first tooth usually appears around 6 months old. Typically, the first teeth to come in are almost always the lower front teeth (the lower central incisors), and most children will usually have all of their baby teeth by age 3. Baby's First Tooth Although the average age for getting their first baby tooth is 6 months, some infants don't get their first tooth until they are 14 or 15 months old. Others can begin teething and get an early baby tooth at 3 months.