Here’s a picture from the flag ceremony at the ‘rodeo’ we have at camp at the end of our 2 week session which has campers doing the final horse session before they become helpers. I’m the one with the girl scout flag. I’m mostly an english rider hence the short stirrup length. The horse I am on is about 9 years old judged by her teeth and I’m pretty sure she is a TB or TB cross. We rent the horses from a horse broker for the summer. (Same horse from this post http://www.judgemyride.net/winners-circle/pasture-racing.html) Judge if you’d like. Click to enlarge.
How much fun! How wonderful as well that you had horses who were okay with the flags and so great.
I would say the stirrups for sure need to come down two holes if not three depending on the saddle so you can stretch down into your heel comfortable and have a very slight bend in your knee. Great heel down though!! I would like to see you stretch up through your abdominals and lift through your chest so you are sitting straighter and taller with your shoulders picked up and rolled back so there is no rounding of the back and no slight tilt forward. If you also lift up with your chin that will help you to stay a little more centered and lifted. You can also lift your rein hand slightly so you are a little straighter from elbow to hand.
In your canter photo you want to lift up through the inside, left side of your body and then bring your right shoulder up and back so you are lifting up and back but also picking up the inside of your body and bringing the outside back to fix just a slight twist through your body.
You look great and keep having fun!!