I have trouble with the concept of "quantifying" my abilities, so, I've given up on trying.
Here's the thing - your abilities are relative, and can vary from day to day. First of all, in order to really "measure" something, you need to have something against which to compare it. So, do you compare yourself to your instructor? To your fellow training partners? Is that really fair? I don't think so - the fact is you should only really be measuring your progress vs. yourself. Do you feel that you're improving? No? You're wrong. If you are working at it, you're improving. Maybe not at the rate you would like, or maybe even faster. Who cares? Can you move better than when you started? Are you putting forth a daily effort? Are you challenging yourself? Good enough, I say.
In essence, you should ask yourself why you're training, and what your goals are. Are you satisfied with your progress in that context? Good enough. Take pride in your success, relax, and have a beer.