It would help to see a video of this, because I don't think you are pressing hard enough let alone pressing too much. If you were pressing too much, your horse would give a pain reaction or spook. She seems to be ignoring your aids, therefore you aren't pressing her enough. If she doesn't move left off your right leg, you are going to have to keep pressing until she does. A crop would probably help if your leg aids still aren't enough. When she ignores your leg aid, you can give her a tap on the hind so she will listen to your leg. Remember to remain calm, assertive, and persistent. You don't want to feel hesitant or doubtful but you definitely don't want to feel angry either. She will learn that once she does what you want, you will take off the pressure and both of you will be content. If it helps, you can lunge her down in that end before you get on so both of you are more prepared to ride in that end of the arena.
"The trouble with the world is that the stupid are certain and the intelligent are full of doubt"