No one in the world can give you an undoubtedly correct answer to that question right now. 3 months was always enough before. Now, there's no data to support that individuals who studied 3 months or less did well on the new MCAT, because the scores haven't been released. The problem with this question is it is basically asking people to give you an answer they don't have, which may potentially mislead you. But then again, you may be already misled as you are. This is all not to mention that, even if there was data, you don't know exactly how your own preparation will go. Things happen. Maybe at 2.5 months, you're at 60th percentile, but you want to be 80+ (your only mode of measurement for this, by the way, is a single official AAMC test). You'll probably want to study more (or go DO). But then you've burned your one quasi-accurate (claims of psych/soc not being the same on the real thing) measuring tool, and now you have no way of knowing where you really stand outside of your own feel of "comfort" with the material.
This is not an easy situation - frankly, it's bad (albeit equally bad for all, so it is good the test is competition-based). If we could simplify it and package it up neatly for everyone to just go down the list and check the boxes (like it was before), you wouldn't even have to ask this question. So, then, your question answers itself.