Is there an advantage to applying at an earlier deadline?
Regions are filled on a first-come, first-served basis based on regional selections at each application deadline. Given this, some regions may be closed to new corps members by the time someone applies at a later deadline. Applying earlier may be advantageous if you have a particular region you would like to teach in.
There are additional advantages to applying to the first or second deadline. You'll have more time to take certification exams and complete your pre-work in advance of summer training. This additional time can also be very helpful as you plan for the transition into the corps and a potential move to a new community.