Critique us :P

Very nice little mare you have on your hands. Others have already pointed out what I would say on your position so I won't comment.
I would like to see her a little looser, I like to have my babies nice and big, loose and swinging more than up with the poll at the highest point. She looks far more relaxed in the photo's where head neck is being carried lower.
At this stage, all you want if for her to go, stop and turn more than look pretty. Have her react immediately off your aids and then work from there. Some trot-canter-trot transitions will really help you to warm up her back and get her loose, but because she's only young don't over do it.
Lots of changes of rein and transitions will get her nice and loose. The biggest thing is to have her relaxed through her back to help her build up those muscles. it will take a while for her back to develop enough to get true swing and throughness, but to develop that you want to get her working actively behind and light in the bridle.

Good luck with her, she's a very flashy little mare!

Oh, I love her! She's GORGEOUS. And the fundamentals of your position are quite solid - with some minor tweaks you'll look great, and be super effective.

The number one thing I noticed in all the pictures is that you're riding the horse "back to front." Basically, you want to work on having a much lighter contact on the reins, and have the energy from her hind end push her into the contact. My OTTB came to me reeeally on the forehand and heavy, and your girl isn't as bad as he was, for sure! With some concentrated schooling, you'll get there fairly quickly.
The best thing you can start to do is warm her up on a loose rein with a lot of leg, to get her really active behind. Basically, let her have her nose up in the air, and just focus on the energy. It'll feel too fast, and that's okay. Then, after she's really moving off your leg nicely and warmed up, start to take contact - very elastic and giving on your inside rein, and more stable (without pulling) on your outside. For every ounce of pressure on the reins, you need to add an ounce of leg, or she'll just slow down. Learn to half-halt with your seat, your legs, and your outside rein, and then you can balance her like that. The inside rein can be "squeezed" - go from the same stability as your outside rein with little 'gives'. Basically, the gives shouldn't be super visible - just open your fingers or move your hand forward a bit, and just for as long as it takes to say the word 'give.'
Riding like this will help you achieve the coveted 'inside leg to outside rein' that people talk about. Once you both get used to it, you'll be able to literally push her balance from your inside leg over to the outside, and in doing so, she'll bring her hind end underneath herself and go "on the bit." A good test to see if you're doing it right is to slowly give both reins. If her head immediately pops up, she isn't engaged, and you've been riding with too much hand and not enough leg. If she remains super balanced and reaches down for contact, you're doing it right.
Hope that all made sense!