I'm going to end up going against the grain here, but I think in your specific case it is too early to be hardcore (mentally). The test is a quite a ways away. You did content review over the summer, so in essence you have already started. What you need to do for a Janaury exam, four and a half months away, is plenty of practice passages and lots and lots of full length exams.
The very best thing you could do at this juncture is to set a realistic schedule from your test date backwards. Figure out what FLs you plan to do and schedule those. You want to also schedule days to thoroughly go over the exam with a fine-toothed comb and correct your errors. Your last FL/review should be about a week before your exam. After your FLs are scheduled, fill in mini review exams (if you have them available). Keep filling in the remaining dates with packs of 5, 10, and 15 passages covering specific topics (using the AAMC list would be best).
What you'll find is that if you plan on 15 FLs and 15 FL review days plus a one-week cushion at the end, there are still 106 days of preparation. At ten passages a day on average, that's 1060 passages, which is really great. Build your schedule and official start date around the amount of passages you plan to do. Whatever day you decide is your start date, get it mentally set in your head.
But be realistic that you already have started and now it's a matter of getting a schedule and routine to follow. A benefit to taking a prep class is that they assign you a start date. But keep in mind that they set their dates according to enrollment trends and not ideal schedules (otherwise every schedule would be pretty similar), so you can use one as a model but don't be afraid to modify to fit your needs.
