What I love about centaur transformations is how drastic the shift in form is for the individual. From a normal human to hybrid form whose lower body is that of an entire horse's, which will makes many things quite complicated for her. But it's always nice when something else changes about them, such as their face acquiring more equine features, as you have done!
The shot of her feet changing really stands out for me. I find the act of them enlongating quite captivating, possibly because the change is anatomically correct in regards to that the lower portion of a horse's leg is homologous to the human hand/foot, consisting of the metacarpal and metatarsal for the front and rear legs, respectively. I'm a big fan of transformations which try to keep anatomical correctiveness in mind as much as possible, as it can make the transformation all the more concrete and real. Of course you can't do that all the time, but it's still something I like to see.
Hope she doesn't mind her new form too much; I think she looks quite lovely!