The common age for kids to start losing their baby teeth is about 6 years old, according to the Mayo Clinic. However, some children start losing their baby teeth a couple years earlier or later, depending on the child's individual rate of development.
Baby teeth, or primary teeth, are essentially the place holders for a child's later set of adult teeth. These place holder teeth, 20 in total, all get replaced by the time a child reaches the age of 12 or 13, as noted by KidsHealth. Each tooth falls out as a new adult, or permanent, tooth grows underneath, eventually pushing out the baby tooth and taking a permanent space within the mouth.