Yeah, that's getting to be a bit late, considering you'd still have to complete secondaries, you won't be seeing interview invites until mid-October probably at the very earliest if you churn out those secondary essays as fast as possible.
It also depends on your GPA. If you have an average/below average GPA, applying late can definitely hurt you, whereas you might fare better applying early. A very strong candidate can afford applying a little later, but you'll definitely be playing the waiting game for interviews and decisions since you'll be interviewing later in the cycle.
If you do decide to apply, send your AMCAS to just one school over the summer so you can get verified and just wait for the MCAT score. Then when your score comes in, you can add more schools and you will automatically be complete and ready for secondaries at those schools.
