Whimsy is stunning! She is an Azteca, no? Really beautiful. You two look fantastic together. For one who hasnt' ridden for awhile, you look good. You are sitting upright and looking up. I think all those shots were at walk, so it would be fun to see some shots form a lesson with trot and canter (maybe not canter yet, for such agreen horse, no?)
Anyway here's what I see:
You lean forward just a touch. Your pelvis seems in a good classical orientation, but your upper body is angled too far forward. Looks a little "tentative". However, for a young horse, if your objective is to stay off her back, then it's understandable.
You have pulled your hands downward in the third shot and it looks a little off, the angle will pull the bit downward onto the horse's bars. Try to keep your hands up, not downward pull.
Really not much to say. You guys will go far.