I, too , thought the horse looked a bit green. What I see is that she is not engaged. I mean, she is strung out, leaving her hind end hanging out behind her, not picking up her feet , but rather kind of shuffling along through the sand, and bracing her back. With a NSH it is always challenging because they do tend to be hot and want to be very bracing in the neck and back. She needs lots of warm up where you get her moving freely forward and work on encouraging her to reach down and foreward with her neck and reach well under herself with her hind.
Make sure sheis bending through her rib cage and not just in her neck. Also, point your toes forwards, not to the side. Your stirrups look a little long for jumping though so that might be the reason you're doing that. Keep your collarbones broad by rolling them up back and down. Also remember to keep your elbows closer to your hips, but still allow up and down movement through them. Keep a straight line between your ears, hips and heels (look at pictures 4&6). The last picture looks pretty good apart from your toes pointing out... good job :) This would be a harder horse to event because she looks so stiff and isn't flexing or engaging her hind end. Do you lease her or is she a lesson pony?
PS- you can tell that she isn't engaged in her hind end because she isn't over tracking... her hind leg should step in the hoof print from her front leg when trotting. If she does this she will also have a rounder back and more compressed shape