Even if, even if, you studied really hard, covered all the material on your own, and did really well on the MCAT without having taken the courses...
You would still have to take the classes to satisfy the med school pre-reqs and this would be a 2+ year process to cover all those courses. SO while you're working on those classes, your MCAT score is expiring.
Maybe you get in one app cycle before you have to take it again, maybe you get lucky and get accepted the first time around. But maybe you don't. And then you have to take the test again, and risk getting a worse score (if it was good to start with).
Why would you do that to yourself? Why not take it when you're most prepared and closer to actually applying?
Also if you still think the scoring is 3-45, then you clearly need to read up more on the test, because that's so 2 years ago.