Mods, please move this thread-thanks.
I personally think that aiming for when you want to start med school is not the right approach. I'd say focus on studying for the MCAT, do well on it, and then based on the result, apply to med school appropriately.
Most people don't find the MCAT to be the most pleasant test to study for, and you'll need time to adequately study for it. You may prove me wrong, but that's probably a 'good problem'.
That said, if you're still stubborn and all you can think about is Fall 2016, then i'd say you should have your MCAT done and scored by July of 2016. But, easier said than done.