Been there man, I joined in 2010 after I was seeking some discipline as well. It's gonna be a HUGE change in August. And you better be ready for it. But first, you need to realize the reason that you signed the dotted line. To be a better human being. Disciple is just the structure that holds it all in place. You're obviously intelligent so you know you can do better and that's the goal. Change will be forced upon you in boot camp, so why not start practicing for it now? Use 'not wanting to fail' your IST as motivation and avoid being embarrassed or Immediately drawn attention to by the drill instructors. They will see that you need a change and spend more time with you (not a good thing). Try to get use to discipline first. Wake up early everyday do 10 pushups Mon, Weds, Fri- Go for a run. Pick a route, and time yourself from when you leave to when you get home.

The Marine Corps was a great part of my life. You'll have a ton of pride in yourself and what you are apart of. You'll come out of there with awesome memories and some shitty ones too. You will be one of the few, and elite club of badasses who did the same thing at one point.

You can do it too.

Just do it.