I agree, the first day is the most important because you will be setting a routine, but if you enter with all you got you will succeed, no place to relax though, no way!
First days are stressful days since you have to get all your paperwork done. Then you are trying to get a feel for how the drill instructors are going to treat you. Its all worth it if your head is in the game.
It varies but I would personally think it is difficult even when you got all the papers done. Since there are important forms you need to sign before starting the academy. Then you have to know where to go since there places you would need to be familiarized with.Actually I thought that once you're in all the paperworks are already dealt with and you just start working on your physical and mental preparation no?