I really think it's an evolution that takes time to develop. You have heard all the hips up, shoulders back, stand tall, and none of it is wrong, but you have to physically and mentally, be able to do it and that takes time. It's not a switch you flip. I believe there is a lot of muscle involved in holding the correct position, and the people that do it best have put the time in to develop it, but are largely unaware that it even exists. At the same time your brain needs to learn how to comfortably take that position, and it's incremental. Your body position looks about typical for the time you have in it. Be patient, be aware, you are on the same journey as everyone else only at a different time frame.