Babies typically start teething between 4 and 7 months of age, although it can begin as early as 3 months or as late as 12 months. In rare cases, babies can be born with teeth or have teeth emerge within the first few weeks of life. The first teeth to appear are usually the bottom front teeth (lower central incisors). Signs of teething can include irritability, swollen gums, drooling, and chewing on objects. The teething process continues as more teeth come in, typically lasting until around 2 to 3 years when the full set of baby teeth appears.