She looks like she may even be younger than the estimated age, from the photo.. Is there any way pictures of the tattoos on her legs could be taken? If we can see how they are done, we could tell if they are professionally done or home made style tattoos. If they are professionally done, the pictures could be distributed to local tattoo shops in case anyone recognizes the tattoo. If she had gotten the tattoo done in a shop in Ga, then it is possible they saved her records. (usually a sheet which is like a waiver so that the person getting the tattoo is aware that any problems with the aftercare is not the shop's fault, and also name, age, if young enough, a photocopy of id, and written description of the tattoo.
They could also hang up flyers with the tattoo's picture in the shops so that if anyone recognizes it, they can call in.