I agree with everyone above. For a start being a racer then a broodmare, she probably has no idea what the hell your asking her to do. Bending and working from behind isn't in her vocab yet.
I would take it slow and start basic. Sort one problem at a time. If your worried about the rushing...
all great advice love grid work. In general remember for the front end that no matter what exercises you are doing always try and put in another stride rather and go on a long one. Short and deep to get them in the air.
For the backend technique, well all you can do is make sure you stay...