It will be fine, don't worry. Be happy you are at this stage and are doing something about what you are struggling with.

In terms of what outcome you are hoping for, I would be focused on getting an accurate diagnosis whatever it is so that you can get proper treatment. My advice is to take a wide array of tests, questionnaires and the physical tests (the computerized tests like TOVA etc) along with your therapists/psychiatrists assessment, since not all tests are 100% reliable and they can give false positives and false negatives.