I agree with you needing to put more weight in your outside stirrup while turning. You are putting your weight to the inside, which will make the horse drop it's shoulder and become unbalanced, often times speeding up. Keeping your weight to the outside will help.
Also watch your legs. At times they start to get in front of you a bit. Also work on deepening your heels and warapping your legs around the horse. It's hard to really see from still photos, but it looks like you are just perched on the horse, not really RIDING the horse. (I could be mistaken without the video, though).
Overall your position looks nice, like you have a good foundation to go from. Best of luck to you.