My school has an average class size of around 100, and I'm literally the second kid in the school's history to go to a service academy. I received an LOA on November 15th, 2013. Not a recruited athlete. Everything plays a part in your application and worrying about something like your high school rating (Which you can't change--unless you want to transfer to a different school. Yikes!) would be fruitless and your own uncertainty about your school's reputability should give you motivation to work on aspects of your application that you CAN improve.