The color combination is good. The Backpack might not be quite the same as canon, but it has a realistic appearance.
Her sweater is good; a bit baggy but it looks comfortable and concealing. Exactly like the written description!
On the downside, the facial features on the left seem a trifle large for the face. A Roman nose might be good choice for a horse whisperer, but nothing I've read so far indicates a southern European background for Elizabeth.
Her pants here look like sweat pants. Comfy yes, and my apologies, but it gives her not so much of a Love Interest appearance and more of a 'telly-tubby' look.
Boots look good; sensible.
Kind of a side question here, but how tall is Elizabeth? If she's about 5' 8" (average height), that is one massive horse.
This is just my opinion though. Like a pretzel, it's best when taken with salt.