So fun to see these photos, @jemimajvr! Nicely done, and well edited!
I think the main area that I could see improvement for these photos would be in composition, although I also understand that action shots like these can be challenging to nail stellar compositions on. 🙂 The backgrounds in the first two pictures seem generally busy & distracting, and the background in the second photo intersects with the subject’s head. In the third photo, it would be epic if the horse had more of the mountain as a backdrop vs the trees – I don’t know if you could get lower or how much you could move around to compose a little differently there for a more dynamic shot.
Other than that though, like I said – very nicely edited, and these are good pictures!