I would assume that she filled out some bio form years ago with that info and it has been copied around forever and she doesn't care. I have seen a bunch of other woman claim to be about that height and weight and they look about like her. I wouldn't be shocked if it is about right. I also wouldn't be shocked if it is off by 2" and 10lbs.
. Look at the width of her shoulder bones (easy to see :)) and compare see how she is as smaller than some girls 3-4" shorter than her. Or look at her hips which are a bit harder. She is absurdly small framed. That being said, those arms are at kiprop level of thinness.
I have no clue if she has an eating disorder. But people have been saying she is going to crash and burn for 5 years now. She was a twig as a 17 . year old and is one now also. And people have been predicting her crashing and burning in every article about her since then. Thats is a long for a person with an eating disorder to survive and thrive. She might just be the freak whose body just wants to be at this weight given how much she trains. Or maybe she is t he freak that makes it 6 years instead of the 3 that most girls seem to last.
You would hope that the are monitoring it closely. Even if she doesn't have a disorder, we are . talking about the levels where you have to make sure not to lose 2lbs accidentally.