Hey, as a military guy I can say waiting and losing a few seniority spots is not the end of the world. DO NOT DO THIS (take the earlier class) IF YOU LOSE TIME WITH YOUR FAMILY FOR SUMMER. This job is in many respects more arduous than dealing with military deployment cycles so please think twice. You will most definitely hear many people say what is considered a commandment to them : "Seniority is everything" but hey, you're coming to a 14k plus pilot airline. a few classes will not make a difference, and may even benefit your initial assignment in some way which you won't know until it happens. Enjoy a break, especially if you get to do things you want to do. You will see being a civilian professional aircrew member brings with it a substantial loss of independence and scheduling certainty for a while.