I think it's the 20 year old too. The reason I think so, is because it's easier to make someone look older, than look younger. The only thing that really stood out in the older pictures, is that her hands are too young. So, she's obviously younger.
I too want to know how we find out the real answer. Also wondering what the point was, aside from being neat to see....? I almost feel like this is really just advertising in disguise (since every link on the page brings you to an ad redirected by dealstudio.com).