So, as someone who has been in many barns and lesson programs, with a lot of people at different levels, here's my take:
You are not ready to jump.
Just from your two posts, it seems that jumping is the end all be all for you and you have stopped applying yourself to your trainer's interests.
Ground/flat work, and a solid position is essential to being able to jump safely for both you and the horse.
I see time after time, barn after barn, people jumping far before they're ready to jump because that's what keeps people riding and paying and wanting to come. No longer is it a school of being confident, able, and strong enough to do so. No, sadly, allowing anyone to pop around a course of cross rails on a saintly school horse pays the bills for a lot of lesson programs.
I remember thinking - and my parents backing up the thinking - that the coach I grew up riding with was holding me back, not allowing me to jump with the rest of the lessons, making me flat around in my two point for hours and hours, sometimes causing me to cry.
You know what?
I turned out way stronger of a rider because of it.
When I went off and decided to DIY the start of my hunter career from eventing guess what?
I went up in height at that first show and fell off in every round because my horse was smart enough to say 'heckaroo no.'
I thought I knew that I was ready to do things and I was not. I wasn't applying myself fully, I wasn't strong enough, and I didn't have enough experience nor understanding of the how's, why's, and mechanics.
Looking back I see things that I should have been able to do before being allowed to jump around that I couldn't. I couldn't find a distance to a pole on the ground. Couldn't shorten and lengthen my horse's stride properly, chipped or left out strides to small courses...
But that's riding, too. Learning as you go. Making mistakes. Looking back and going 'dang we got away with a lot of bad decisions ten years ago!'
I grew up in my teen years angry that everyone else was doing things I could not, and blamed my trainers or my parents or my horses or something, but looking back now, ten or so years later, I'm so happy things happened as they did. It took me a long time but it made me a really strong rider and horsewoman.
I didn't jump a lot when I was a kid, but now I have a horse that I can jump 5' on and be confident and strong about it!
TL;DR ending - trust the process. Instead of saying 'I can't do this, why?' Ask 'if I'm not ready to jump yet, what do I need to do to better ready myself?'
In the interim, read books! Watch videos! Even as someone who rides 3 horses a day, competes on the A and AA circuit, has ridden with big and small names, I watch riders all the time. I read books by the old masters and talk with the people around me on the 'what could I do better? What was right that I did and what wasn't?'
I agree with having an open and honest talk with your instructor is a good thing - especially with your parents present so they understand too! But don't skip to another trainer just because this one isn't letting you do what you want.
The only reason I'd have you move, if you were my child, is if the trainer cannot give you a detailed and straight answer as to why you're not allowed to do something.