you know I love your horse. He's too cute!
What sticks out sorely is that you have your elbows stiff and your hands much too low. I am sorry , but it looks a bit like you are driving a wheelbarrow. That isn't meant to sound harsh, becuase I know you are trying to learn and grow.
But, look at the last video where you are sitting up and holding with one hand. SOOO much nicer. It's not just that you are one handing, but that you are not trying to pull , or hold, his head in some position.
Get those hands up, dear, and sit up , ride proud and centered with your hands connected to your core, not out stiff like two sticks pointing at the ground.
You'll get there!