Depends on how well you do and your current stats. The weaker your score and stats usually the better to submit MUCH earlier. However the earlier MCAT with less prep often means a weaker score. Why are you waiting so long to take it? Studying or something else? If you don't think you can get a 504+ then don't rush it.
Don't take it until absolutely ready and rock it. Study your brains out between now and then. Otherwise you might be looking at applying again next yr. You'll be a Sept/October application either way so you really need to shine to have a shot.
Best of luck
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