As far as your baseline, your abilities are somewhere around a 580 right now (average of your three scores). In the future, GMATPrep CATs are the most accurate measure of your abilities and when using third party CATs, try to stick with the same set.
MGMAT are great because you can get six for about $15.
And that is a good point from GMAT Pill - the important thing is to prep effectively for 2-3 weeks now and then retake a CAT to measure your improvement.
What is your goal score?
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