Your tortoise is most likely a G. p. babcocki, as the previous owner would have been told it was a G. p. pardalis when she purchased it (they are almost always sold for a premium and specifically identified as G. p. pardalis). Most of the characteristics of your tortoise are also G. p. Babcocki.
My new book on Leopard Tortoises (available at http/www.leopardtortoisebook.com or contact me at richardfife@theriver.com) has some great information on the subspecies. 13-inches is not a big leopard tortoise. Most adult G. p. babcocki are from 13 to 18 inches (all my adult females are between 16 to 18 inches). Actually there are populations of G. p. babcocki that are over 24-inches (that’s right G. p. babcocki) and come from Somalia.
Adult G. p. pardalis are usually between 16 and 19 inches, with some specific localities where they grow to 24-inches. The double spots seen on hatchings are the best indicator of the subspecies but I have pictures, in my Leopard Tortoise Book, of G. p. pardalis, which I found in Bloomfontien South Africa that do not have double spots.