Realistically, unless you have a competitive nomination, eg, Presidential, you are not likely to receive an offer of appointment until after the first of the year when the congressional noms are reported to USNA. Also, consider that prior to the first of the year packet reviews are performed typically one day a week whereas after the first of the year (mid Jan) the packets normally are reviewed two days a week.
BTW, remember to keep the information in your packet updated with grades, achievements, etc. If you don't tell them, likely they won't know about the changes.