Hi there, You have a very cute pony - and you look like a rider who is willing to learn and grow......so please take my critique, from someone who cares.
99% of refusals - is rider error.
I will explain why - horses jump blindly. They rely 100% on their rider to guide them clearly, functionally and safely.
Your horse cannot see the fence. They see it a few feet away from them - it is in 2's. Then the get closer, the fence now is 1. Then when they are 1, 2 strides away...they can no longer see the fence.
They rely SO MUCH ON US AS THEIR RIDERS TO DO OUR JOBS CORRECTLY.
It is us who unbalances them. It is us who makes mistakes in the saddle, creating the domino effect. Not the horse.
There are many horses out there, who will jump for their rider, regardless of what is going on ontop of them - covering their riders patunks. These horses, are not teaching their riders anything.
You are lucky to have a pony who is trying to teach you.
YOU must beable to approach the fence RHYTHMICALLY, STEADY, FLUID, UNDER CONTROL and most importantly - FUNCTIONALLY.
Your form in the saddle is very important. You are out, so is your horse.
Lets talk about your form first and foremost -
1) Stirrups too long. Shorten them a hole or two. Why do I say this? Look at how loud your legs are, and how little base of security you have in your tack. You need to shorten them, so that your lower leg and heels can be your base of security.
Everyone is telling you to not jump ahead - but lets ask what is physcially causing you jumping ahead.
No base of security in your lower leg, no base of security in your heel. Because your leathes are a tad too long.
Your legs are flying everywhere at the canter - which is also causing your seat to be very loud on approach to the fence.
2) They are way to far back on your foot. They should be at the ball of your toes - where the outside bar of the iron is at your pinky toe, and the inside of the bar of the iron at he ball of your big toe.
Due to these 2 big issues.....your heels are not being permitted to do their job - which is ANCHOR YOU in your tack.
Once you get the correct length of your leathes, and the correct placement of your iron......allow your heels to do their job. Allow the weight from your upper body, flow thorugh your seat, down into your legs and down into your heels.
3) Your heels should be taking everything - all weight, all energy.
4) Your legs should be - and always be - AT THE GIRTH. You are not just to be ontop of your horse, but you are to be wrapped around your horse. Imagine your leg getting long, allow the weight to flow into your heels, and lock your legs at the girth.
I HIGHLY RECOMMEND YOU DO ALLOT OF 2 POINT WORK ON AND OFF THE LUNGE LINE! Get those leg muscles to remember where they need to always be - at the girth. Get those heels working and doing their job - taking all your bodies weight.
Due to lack of functionallity in your lower leg and heels - the domino effect of negative form over fences occurs.
You reach for a base of support in the wrong places of your body aka knee pinching, gripping, standing up in your irons etc, etc, etc - and you have now caused incorrect, unsafe form over fences.
Such as the picture if your Avatar - you are jumping ahead. All your bodies weight, is now tossed onto your horses forehand *shoulders* making his job, that much harder to get over the fence.
Your job, is to get him to the base of the fence in a rhythmical, steady, fluid, functional manner - his job is to get you over the fence. Without your important part...the rest cannot occur.
So your upper body, now flings forward, and your lower body, flings behind you. Your crotch goes over the pommel of your saddle and all of your weight, is now dispursed on your horses front end.
Your weight, should always remain - 100% of the time, over the center of your horses gravity.
Fix your leathers, fix your irons, work on your heels and work on strengthening your lower leg to keep it at the girth.
Work on SITTING AND WAITING FOR YOUR HORSE to close the angle. That is HIS job - NOT yours. You must remain solid in your seat, and allow your horse to come up to you.
Your upper body must remain tall, your seat must remain engaging, and your lower leg must support and lift. You must keep your shoulders back - where as instead...you are dropping them.
Remember - your horse is to lift you out of your tack, your horse is to close the angle..not you. You must remain solid and supportive.
What exactly is occuring - when your pony refuses? YOU.
You are not approaching the fence rhythmically. You are not approaching the fence in a controlled manner. Your form is all over the place, you are unbalanced and not anchored in your tack, and then you drop your shoulders, and say "OK, NOW YOU DO IT" and your pony says " YEAH RIGHT"
You as your horses rider, must support your horse at all times, to, over and after a fence.
Learn to remain solid in your seat. Sit and wait for your horse to LIFT you out of your tack - not the other way around. Your horse will do the rest.....that is not your job.
If I were your coach - I would take you away from the Verticle. I would put you on the lunge line and work, work, work on solidifying your body parts, to make you a more functional rider.
Also, when you are going around the corner to the fence - your horse is drifting to the outside, with his shoulder popped. His center of gravity is no longer under him and you are pulling head head to the inside.
He needs proper guidance from his rider.
VEERING OUT OF THE FENCE
Again, this is all due to rider error. You have not set your horse up accordingly to get over the fence properly. You are all over the place - again, this will come with correct lunge line work.
Someone told you to use your inside rein when he veers out - which is incorrect.
You use your OUTSIDE AIDS. But you cannot do this if you are not put together yourself on approach to the fence.
When you are approaching the fence, and you feel your horse starting to veer. Lets say he is veering to the left side of the fence.....You sit deep, use your left leg at his ribs and your left rein at his shoulders.
You want to keep that outside shoulder from popping out from under himself, and you want to keep his center of balance under him.
If I let go of my lower leg with my TB at a fence, if I get ahead at a fence, if I drop my shoulders at a fence....my TB will drop me in a heart beat.
It takes a horse to refuse on you - to learn.
I am suprised your coach hasn't worked on any of this with you.
All the best to you,