Yea. what justamom said. My son put in his application last year and was totally completed by July 19th. That included the entire application, letters from teachers, CFA, Medical, Nomination, etc... Nothing was left to do. So, the end of August is fine. The earlier the better. They start opening them up and reviewing the first part of September. If yours is early enough, and good enough, then you have a good chance of an LOA or appointment by the first week of November. My son received his appointment letter November 5th. It sure makes for considering the other colleges easier when the academy is your first choice.
The only thing you want to make real sure of is that you get your grades from college inputted as soon as you know them. Chances are, if you had a mediocre high school transcript, that you won't get an early LOA/Appointment. That's because they and those who are asked to nominate you, don't have any college grades to work with yet. So, as soon as the semester is over, you want to get grades in there.
The hardest thing you have to do is to get a nomination. Most congressman/senators do their interviews and such after November. Being in college and ROTC will help, but your reps might still look at your high school grades being that's all they have to work with. Unless you are eligible for a presidential, VP, or ROTC; you really have to sell yourself to your rep to get an interview and nomination. I would contact them ASAP and ask them what they want you to do. Our reps let my son know exactly what they wanted to see. Luckily we didn't need to use the rep's nomination, but it was nice to know just in case.
Also, get close to your ROTC chain of command and let them know your desires and intentions. They can help more than most in getting you through filling all the blocks. Good luck... Mike....