My dad and I are building my Greek tortoise a cage. It will be about 16 inches by 64 inches. It's the size of my one shelf in my room. Is that a good size? He will only be there about 3 years until I go to college in which I will have to get an off campus apartment for him and I. When I get that he will get a MUCH larger cage. But for now is the cage a good size? He is a few years old. His shell is about 4 inches. I just don't want to deprive him and cause him to feel stressed or cause his growth to be stunted. Thanks!