I've already given you advice on 2 of your threads already.
You are looking up, that's a bonus. And I am glad that you can see some of your faults.
You have allot of potential, all riders do - but it is what you are willing to do with your faults, to become a stronger, more educated, functional rider.
We only know as much as our coaches know. We only know what they teach us. Our horses, only know as much as we know and what we are willing to teach them.
That is why I have a huge beef with unfunctional coaches, turning out unfunctional riders.
I still stand by what I said before - your coach should be working on allot of your basics and fundamentals first, before A) putting you on a green pony B) allowing you over fences.
I wish my coaches did that with me. I'd be allot stronger of a rider today if they had not permitted holes in my training.
You are lucky to be young - because you still have a chance to have an educated coach mould you into a talented rider. Me - it takes allot longer for me to change my old habits.....to correct the holes that my uneducated coaches allowed in my training.
1) You have no stabillity in your lower leg.
Your lower leg is not strong enough to support you over the fence. You need to work allot on keeping your lower leg at the girth.
Imagine yourself wrapped around your horse. Not just being ontop - you have to be around her.
Work on lots of two point. Lots, lots, lots, lots, lots. Push those legs to the girth, wrap them around and keep them there. Train those leg muscles as to where they need to be.
Get on the lunge line. Do this without reins. Work on stabalizing your lower leg, and your seat. Your center of balance and gravity. Work on your core *your tummy muscles*
All this will help
2) Iron placement
Your irons are too far back on your foot. Your heels cannot deepen when your irons are not helping you. They should be on the balls of your toes - the outside bar should be at your pinky toe, and the inside bar should be at the ball of your big toe
3) OPEN your knees.
BUT you cannot do this, when you have no lower leg stabillity. They go hand in hand. Because you have no lower leg stabillity, you turn to pinching your knees for that base of security in your tack.
Due to this, your lower leg flings back, and your upper body flings forward.
OPEN your knees.
4) Deepen your heels. Your heels must be allowed to do their job. They must, must, must, must take the weight from your body. ALWAYS. They must be permitted to anchor you into your tack.
If you strengthened your lower leg, and you allowed your heels to do their job - you wont be pinching your knees.
5) You are riding the fence, and not your horse.
You know the fence is there. Your horse knows the fence is there - so why are you staring at it?
Learn to ride your horses rhythm - your horse, which is the most important factor to jumping, needs to be your main focal point. Ride his rhythm - keep him rhythmical under you. Ride his canter. Focus on your leg, heels, seat, upper body.
Allow the fence to come to you, it isn't a race to get to the fence. The moment you stare at the fence and anticipate it, you are now riding the fence and not your horse.
6) Allow your horse to do her job.
Her job is to get you over the fence, YOUR job is to get her to the base in a safe, controlled, rounded, rhythmical pace.
You are little, you are small - you cannot get this pony over the fence...only she can.
Your job is to stay out of her way - just by sitting and remaining solid and leaving her alone.
Get her to the base, and allow her to do the rest.
You need to learn to sit, to wait, to support. She has to lift you out your tack, she has to close the angle - none of that is your responsibllity. Your responsibillity is to remain balanced over her center of gravity.
7) Your seat
Way to out of the saddle. George Morris says that you only need just enough space between your seat and the saddle, where you can fit a hand between. That's it.
Work on allowing your horse to lift you out of your tack. Sit, sit, sit, sit, sit and wait for your horse to do her job.
Remain light in your seat, close your lower leg around the girth, deepen your heels and just wait. Push your seat back towards the cantle.
8) Upper body and release
At the moment, you are closing the angle - throwing all your bodies weight onto your horses forehand, making her job that much xtra harder. Not only, now is she carrying herself, but but you too.
You are not aiding her at all. You need to learn to sit up tall on approach, lighten your seat through your heels and allow her to do her job.
Your release - you should be grabbing mane or have a breast collar on so that you can grab onto it, leaving her face alone.
Again - lunge line work will help with this. My coach has me do mock jumps with reinless lunge line work. I'll be in a canter, with my seat light and my arms positioned as though I am holding the reins. He'll say "jump" and I have to mimic a fence with my position - this way, I am in no way, interfearing with my horse.
Then, we apply that over a fence.
If you were my student. I'd put you on a much more experienced horse.
You need to learn to focus on yourself first. You need a coach who can teach you strong fundamentals *basics* before putting you over fences. You need to learn to stabalize your body, learn where it should be, learn how to keep it there. Learn to use your seat and legs - there is so much you could be doing right now, to be that fabulous rider you so desire to be.
I'd do allot of lunge line with you. Reinless lunge line work at that. You need to strengthen your lower leg, you need to learn to remain with your horse at all times and you need to learn to stay out of their way.
I would have you go over cavaletti's - lots of them, and trot poles.
I would also do allot of flat work with you, teaching you to ride seat into legs into hands.