Congrats on your accomplishments!
Just a tip before I comment on your position. For a show, keep your hair up and under a helmet for a neater look. Swinging braids are quite distracting. Other than that you are turned out to impress!
Overall you are a nice rider, there are just a few things I'd like to point out.
Right now, your stirrup is twisted the wrong way, creating a stiff ankle and prohibiting your weight to sink into your ankles and anchor your leg at the girth.
Position your stirrup so that it is lying diagonaly across the ball of your foot. This will allow greater flexibiliity in your ankle, allowing your heel to act as a shock absorber and therefore increasing suppleness throughout your entire position.
Your leg has slid back a tad, due to either your siff ankle, a pinching knee, or both. Your stirrup length is nice, maybe a tad short. This unstable lower leg is also a reason for...
...your jumping ahead. Quite a bit actually, with your upper body on your horse neck and your seat much too high out of the saddle. Wait for your horse thrust to close your hip angle and lift you out of the tack. Work over many small crossrails to help stop your anticipation.
Your release is nice, with your hands pressing into the crest. Be sure not to break your wrists, this is an unsightly habit.
Your reins look very short, as your hands are quite a ways up her neck and yet you still have a lot of contact. Your mare will enjoy a looser rein so that she can really stretch out and round over the jumps. In the hunter ring, it is sometimes appropriate to ride with a drapey rein to show off your horses form. In a jumper or eq class, a shorter rein is more approapriate as you cannot sacrifice contol.
Your horse is very classy, and looks through the bridle well. I suspect she has a tight front end, but it is difficult for her to snap those knees up because of the exessive weight placed on her front by your overjumping. Once you sit back and straighten up, she will improve.
She is also leaning heavily to her left, I realize that you are about to make a left turn (at least, that is what I am assuming from your head position) but she's dropped her left side and leg. This will only result in a heavy turn after the fence instead of a light and balanced one. Is she stronger on her left or right lead? If she is
left sided, then this leaning may be a habit she has developed.
Overall you two look great and very competitive! Good luck in all of your showing endeavors!!