I agree with all the posts above. Now, my turn! About you pinching with your knees. That's a problem I also used to struggle with. The best way to work on that is flat work, NOT over fences, because it could be verrrrryyy dangerous if your lower leg flies around wherever it pleases. Knees also don't allow your body the spring it needs to absorb the landing; that's what your lower leg is for. So while working on the flat practice with shorter stirrups, having your leg bending at almost a 90 degree angle, then before asking your horse to even go, take your knee off the saddle, roll your toes outward while gently having your heel and ankle closer to the horse than your big toe, stretch your heels comfortably down, and sit up tall and straight. Generally, you want your mid to upper thigh and lower leg doing all the work as far as holding yourself out of the saddle goes. I strongly recommend taking your stirrups off the saddle completely at least once a week or riding bareback to improve this position, and do not let your knee to press into the saddle at all. You physically cannot hold your lower and upper leg correctly against the horse with your knee in that way, it makes you bow-legged. I struggled with this for a long time because I was born bow-legged and my feet still naturally turn inwards when I'm not paying attention to them. Learning to take my knees off the saddle tremendously improved my leg position.