I suggest that you take an official GMATPrep practice test https://www.mba.com/the-gmat/download-fr ... tware.aspx. Those tests are, by far, the best predictors of your score on test day.

The GMATPrep tests use official GMAT questions, and they use the official GMAT scoring algorithm. Also keep in mind that the test-makers collect a lot of data on every single question, and every question has been asked in a formal testing environment, so that the well-prepared test-takers are trying their very best to answer every question. While many test-prep companies have great practice tests, those companies would never suggest that their tests are as accurate as the official practice tests. The 3rd-party tests don't use retired GMAT questions, they don't use the official scoring algorithm, and the data collected on each question cannot be as accurate, because the students taking the tests aren't doing so in a formal testing environment.

So, while 3rd-party tests are great for practicing your test-taking skills, and for identifying weaknesses, you shouldn't use them as the sole basis for determining your readiness to take the GMAT.

Cheers,
Brent