It curves inward to protect the tail when copulating and it takes on a more horizontal shape. In this picture, you can see on this male that the supracaudal fits well inside a rectangle shape.
For a female this size, I would expect the supracaudal to have extended further outwards and come to a point like you see in this adult female.
It's been my experience with most tortoises that the anal scutes are some of last sex-indicators to develop, and can sometimes be confusing in leopards like you see in the male in my first picture. I usually start with the tail, then look at the supracaudal when things are not so obvious.
I've been wrong before...but right now I would bet on 2 males.