Congrats on a successful first show
First - Your turnout is impeccable, both horse and rider. Beautiful shiny horse and great braids. Your well-fitted bridle with buckles and keepers lined up and saddle and pad all fit well and your boots are nice and shiny.
These details show the great respect you have for your horse and your sport
Second - how great to actually ride hunter classes on a real outside course on glass and not in a sand ring??!! What a nice venue! You're now officially spoiled forever
Your flat pictures remind me of hunters in the 70s and 80s in the best way. There's nothing so classic as a beautiful plain dark bay TB on an outside hunter course. Your form is nice here on the flat, but shows some tension which shows up in the o/f pics.
You are jumping ahead of your horse and aren't closing your hip angle over the fences. Notice how your "lady parts" are in front of the pommel in every pic. It should be hovering above the seat, and your elbows went out when you "overjumped" the fences.
Your horse seems very honest - many horses would quit when the rider consistently drops her horse and jumps ahead. Be aware that as the fences get bigger and correct striding becomes more critical, you can lose your horse's confidence quickly if he isn't presented with a doable stride in front of the fence. Do it enough and you will create a stopper
The fences here are too small for your horse to take seriously and I'm guessing that your photographer wasn't a professional show photographer, since all jumping pics show your horse with hind end still on the ground.
If I were your trainer, I'd have you practice endless hours jumping position, with attention to the transition from galloping position into jumping position, both at large and over trot poles, raised cavaletti, and a simple X. Pay attention to scooting your butt back, keeping your back flat, and elbows in. Remember that when your elbows go East and West, they cannot go forward
As the fences get bigger, your horse's mouth will suffer for this. Also, lines of gymnastics are so good for improving your horse's bascule and your jumping position. I would also have you call out striding to fences of varying heights and widths from 2 strides away - "2, 1, GO!" and increase to 3, 4, 5, 6... Its a great exercise for developing your eye for distance.
I really enjoyed seeing your photos. You should be very proud of yourself and your lovely horse!