if you have a pretty good back ground, then 3 months will be more than enough.........i started in may for the mcat and reviewed all the materials by reading kaplan's review...i referenced textbooks if i was a little weak in an area and i did practice problems for that weak area so i could strengthen it......as i reviewed, i would also do review questions given by kaplaln............i finsihed my review in 2 months.......so july and august was all full lengths.......the week of mcats i tried to review the materail to keep it fresh for the big day, but i coudn't.....i tried, but i ended up walking away after about 5 minutes.....its going to get to a point where you know this stuff second nature...review it, strength your weak spots and practice like crazy..........i'd say if you are especially weak in one of the big four, start around november and strengthen that for a couple of months and then jst practice like crazy........you'll learn that its not just konwledge, you have to learn to take the mcat........on myu real mcat, there was formula i dind' know, something about absorbance and concnetratoin...........i forgot it, but was able to figure it out using units............know the basics, but dont' go too detailed with the sciences....
best of luck
nero