I have scoliosis. HAHA Hi, I'm Steph and I have scoliosis. (that struck funny for some reason). I can't remember how old I was, but I know I was in Jr. High when it was diagnosed. For me I ride all cock-eyed to the left and yes it can throw off a horse's balance.
Because I was already riding when it was caught, my trainer made a hard effort to figure out what would work best for me. It was a lot of yelling and stopping to reposition myself on the horse. A lot of "see the difference, try to remember this feeling when you're moving." Also, it was a lot of lunge line lessons, most times with out stirrups, she figured if I fell enough times, I'd figure it out on my own (she was right). She also put me on her horse that was very sensitive to all aids and if I was the slightest bit off, I knew it.
Growing up riding with all that extra effort I was conditioned to get used to feeling like I was riding off balanced, but really wasn't. Now as an adult I spend the majority of my time riding/training on my own. However, because I spend all those years as a kid hearing my trainer, I can still hear her voice as I'm riding. I feel like I give myself a lesson because when I'm on a horse I literally am thinking "shift to the right, what's your shoulder doing, lift your chest up more, use your core muscles, a little more this, a little less that."
Im not sure that really helps your or not. But short end, you have to constantly check yourself. Listen to your trainer, if she she's you're crooked, then fix it and make a mental note of that feeling.
This is what happens when you have democrats in office