Very pretty mare! You both look great together!
Your flat pictures -
The first thing I see is incorrect placement of your iron on your foot. This, is going to deter your leg, heels and ankles to do their job. The iron should be placed on the ball of your toes, where the outter bar is at your pinky toe and the inner bar at the ball of your big toe.
Right now, I se you reaching for your toes for stabillity, when you should be reaching for your heels. Your legs need to beable to do their job -
Seat Into Legs Into Hands.
When your legs cannot work properly due to incorect use of tack - you break that line. Which then leads to a rider resorting to other parts of their body to compensate.
So - correct your iron placement, and work on allowing that weight from your upper body to flow down naturally into your ankles and into your heels. NOW you have a base of security. Now you can achieve stabililty.
What I also see - is you are using the incorrect area of your lower leg on your horses side. You are riding on the back of your calf, when you should be using the inner part of your calf.
What I am going to really suggest is doing allot of 2 point work here. You need to focus on stretching those legs down and long, inner calf at horses side, heels taking bodies weight. Train those muscles as to where they need to be. Train yourself to use your legs correctly.
Your seat is nice, your lower back is nice and I love that you have a tall upper body.
What else I see - is way to open of an elbow angle, way to low of hands. We cannot be effective in lifting our horses up into our aids, if we have unfunctional hands.
We must learn to lift them, carry them properly - that way we can give, take, ask, be asked, soften, be softened, lift, aid, support. When we carry our hands low like this - we risk faulting our balance and our horses.
Our hands drop, so do our shoulders. So does our upper body, so does our head. If you carry them, you aid your form and your balance as well. Also, when we drop - our horses do too.
Right now - your mare is on her forehand, you can correct this by lifting your hands, closing your elbow angle and lifting her back with your legs. Support your horse, lift her up into your aids.
Also, I see way to taught of an inside rein. You aren't giving your horse anything at all. See how tight her mouth is with your inside rein? You must learn to soften and release your inside rein.
We ride inside leg, to outside rein. Our horses must beable to balance and be supported through our outside rein. Right now, she is stiff. Give with your inside rein to reward her. Drive inside leg, into outside rein.
Again with your leathers and irons - use them correctly to help you. To aid your support and balance in your tack.
Get those legs to the girth. 2 point, 2 point, 2 point. Train your leg muscles as to where they need to be. Get those heels down, allow your ankles to aborb your energy and your heels abosorb your weight. Inner calf at girth.
We are not ontop of our horses, we are suppost to be around our horses. We MUST support our horses to the fence - when we loose our lower leg, we fail to do this.
Lift your horse up into you - wrap your lower leg around the girth. Support your horse. Support your form.
Now your biggest fault here - right now - is that you are pinching your knees. Biggest fault in lower level riders today. Riders who aren't being taught properly before they are allowed to go over fences.
Open those knees up - because right now, they are blocking your bodies weight flow to dispurse into your heels. When you pinch, you are NOT allowing your heels to do their job - which is essential to solid form over fences.
Due to your knee pinching, your lower leg fly's out under you, and your upper body going flinging forward.
Open those knees, allow the weight from your upper body to flow down into your heels - allow your heels to anchor you. Get those legs around your horses girth, inner calf.
You must train your lower leg to do it's job properly. You cannot do that when you resort to pinching your knees.
Alright - so what else is happening? You are anticipating the fence. You know that small x rail is there, your horse knows that small x rail is there - so why are you focused on it?
Stop focusing on what is infront of you, and start focusing on riding your horse. Ride your horses rhythm, not the fence. Your horse is the most important factor to this equation of jumping - NOT the fence.
The fence is just a burp in your pathway. Without your horse, you have nothing - so start riding your horse, focus on what is under you, not infront of you.
Your job, is to support your horse to the base of the fence, in a rhythmic, safe, controlled tempo. Your horses job, is the rest.
Focus on where your seat is. Focus on where your lower leg is. Focus on your horse. Rhythm, rhytym, rhythm is the key. Solidity in your form is the key.
Sit, wrap your leg around your horses girth, ride the rhythm, not the fence. Allow the fence to come to you. Look beyond the fence - and pay attention to you and your horse.
Jumping is dressage with speed bumps - all you are doing is flat work with fences in between.
So - you are jumping ahead. See how much space is bewteen your seat and your saddle? See how your crotch is over the pommel of your saddle? You are jumping ahead - riding the fence, not your horse.
Sit!!!! WAIT!!! Your horses job is to lift you out of your tack. Your horses job is to close the anlge - you cannot do that!
When you jump ahead, you also impede your horses abillity to do his job. You throw all your bodies weight onto your horses forehand - instead of remaining centered and balanced over your horse.
You want to AID your horse, not hinder. You want to be a TEAM - this is not a 1 man show.
Ride your horse, not the fence.
1) Proper placement of your iron on your foot
2) Open your knees
3) Stretch your lower leg at the grith, inner calf, wrap around horse
4) Sink down and low - allow horse to lift you out of your tack
When you are going over the fence, push your toosh back - push your ta-ta's out.
What I am also going to suggest - is lunge line work, with no reins.
This will greatly improve your seat and your legs. You will learn to rely on those two aspects of your body, which will improve your position and form all round. You will find your seat really quickly and will learn to use your legs to aid your seat.
You and your horse look great together. She is lovely! You are very lucky to have a dad who comes with you and can get pictures!