Congratulations on graduating, that is a huge accomplishment! I know it seems so far away, but time will fly by! In regard to ICU, just be a sponge - flexible and open to criticism - and you will do wonderfully! No one is expecting anything of you at this point - just that you'll ask questions and perform duties safely. I also never mentioned my interest in CRNA school as I have personally seen colleagues get sabotaged by this (I.e., giving them easier assignments so they don't have the complexity/acuity needed for CRNA school, delaying training on devices/post-ops, etc.).
I would also start studying for the CCRN around the 6-month mark. I know the requirements state 2 years of ICU experience, but as long as you have 1750 hours, you're good to go. I hit this within my first year just by picking up a few shifts here and there. It was also valuable knowledge that improved my nursing care.