Typically, the Admissions Board starts meeting to review applications in late August. However, there is usually a backlog of completed applications at that time so just because yours is complete doesn't necessarily mean it will be reviewed at the first meeting. Also, there is no perfect FIFO ("first in/first out") system.
Note that for those needing an MOC nom, you'll have to wait until your MOCs turn in their slates to be offered an appointment -- although you can get a 3Q decision, or even an LOA, from the Board prior to that time.
Also, for the OP, if you're reapplying, the Board will not look at your packet until first semester college grades are in -- which is typically late January. Does not matter when you turn in everything else -- for reapplying students, USNA wants to see your first semester grades and they'd best be good. Also, you need recs from your college profs whom you've not yet met. So there is no rush. I'd actually wait until sometime during your first semester to submit the majority of your packet. This will also give you more time to reflect and you'll likely write a better (different) essay.