I do mostly ICU nursing (Medicine and Respiratory with some per diem stuff in Burns as well) but I also did a year on a Rapid Response Team as well. I love it!!! Maybe one day when I grow up, I'll do Life Flight, but who knows.  I went into the ICU straight out of school because I knew that was where I wanted to be, and I have never looked back.
You seem like you're on the right track, with the attitude you had trying to get into school-so hold onto it, because you'll need it. And really, if you said that already you've been study study study and not much socially except DG, then I think you'll be fine with the commitment. Like I said earlier, you'll find what balance works for you. Just remember why you wanted it, when times are tough and you want to quit (because you will hit that point).
On a funny note, the shots aren't that bad except the Hepatitis series. That one hurts like a biotch!!  But you'll be fine. Welcome to getting a TB test yearly!!