Ok, I'm going to try and remember how to ride a 20-metre circle.
I was told that your horse should be straight at E and B in a circle but only for a moment. After that you should start bending again. And with the flexion, you should only be able to see the corner of his eye and smidgen of his nose. Outside hand contols the speed, inside hand controls the movement. I was told that a lot of beginner riders give too much with their outside hand and then their horses taken advantage of that and quit the circle. He shouldn't be excessively leaning on your inside leg either, so bump him off it if you need to. I have my first dressage test in February too! :) But I'm doing prelim.