I'd definitely say ornate box turtle. I grew up in Southern Missouri where we had both three-toed box turtles and ornate. Saw a lot of them in the wild. I never particularly noticed "green" heads (or what color their tongues were). They had brown markings on the pastern/bottom side of their shells though.

More about ornates here: http://www.tortoisetrust.org/care/cornata.html

http://www.gpnc.org/ornate.htm

Yours looks like a female to me... They have a lot of special needs. I'd read up on them extensively.