agree with the above to push MCAT test date back. It’s a really nerve wracking thing to take such an important 8 hour test, you really only want to do it when you are scoring in range of your goal score as a confidence boost.
Use 3rd party exams to gauge timing, and to identify content gaps, but don’t emphasize the score. Since the test is different from the AAMC, you want to look for a positive trend.
The low AAMC score indicates that you have content gaps (anything below a 127) and the low cars score indicates you need a better approach to reading/synthesizing info in the passages. Increasing your score here should help boost your other sections since all sections are CARS esque.
If I were in your shoes, I would take 2 months to do the following:
Day 1-30: complete AAMC section bank. This is hard as hell but it will give you an intro to their writing, question, and answer style. Do this under simulated MCAT conditions (59 questions in 95 minutes). Next, go through AAMC CARS q packs, again simulated MCAT conditions to get used to AAMC logic. Third, get a copy of UWorld, on Monday, take the equivalent of half the MCAT under timed conditions (cp/cars, bb/ps). It should take three hours to do. The next day, review all mistakes that you made and thoroughly review the content for each error. Your goal here is to identify content gaps. On Wednesday do another half MCAT, and repeat. Finally, I would do two practice MCATS, non AAMC twice over this month for timing and stamina building. Timing can be a huge factor on the MCAT. Some folks who struggle on practice tests fly through the exam while other who never had issues with time get hung up on a couple of questions and then need to rush. Practicing discipline here is essential.
Day 31-60: All AAMC all the time. Do a weekly timed MCAT. Thoroughly review all errors. Complete all q packs, repeat section bank and cars. What you’re looking to see is a gradual progression where your scores are increasing in each section. Make flash cards for errors that you make and explanations for why an answer is/is not correct.
Hardest thing to do is to push a test date back but I’ve had many friends approach test day hoping for a hail marry like increase of 7 points only to see their scores drop. You’ve got plenty of time to complete the MCAT. Good luck to you.