Originally Posted by RandomHorsey
My trainer says my sturrips have to be that short cause I lose them all the time.
That's just an excuse. The reason you would keep losing your stirrups is because you aren't keeping your heels down and letting your weight sink through your legs and into your heels. In the videos you can see that you have absolutely no weight through your heels and as you mentioned yourself, you have a hard time keeping the stirrup on the balls of your foot. Yes, your stirrups should be shorter for jumping but not used as a way to keep you from losing your stirrups. If I was your trainer, I would spend much more time on flatwork and two point in order to help you distribute your weight through your legs and into your heels. You need to have a good foundation before you move up in jumping height. If you don't have the basics down good, it will all fall apart as the jumps get higher.
Another thing I noticed in the videos is that you really thrust your upper body around at the canter. Concentrate on keeping your upper body tall and letting your hips, seat, and upper legs absorb your pony's movements. Practicing with no stirrups can also help this as you really have to rely on your muscles and balance within to keep a steady position and flowing with your horse.
I honestly think your stirrups are causing you a bunch of problems!
On the other hand, you were doing a great job of looking up where you were going and making that pony go when he broke into a trot! Hard work and going back to the basics will really open of the possibilities for you two and boost your confidence.