Math is important. The continuation of someone's life will depend on your math skills.
I'd also brush up on hormones and their effects, especially the ones that link together, like renin-angiotensin-aldosterone. Any concept that gave you trouble in patho, micro or A&P needs to be reviewed, because you apply it all in nursing.
Finally, I'd get involved with a healthy stress reliever like yoga so that you're sleeping well before you start. Unless you know that you lose weight when stressed, I'd buy your scrubs
a little loose. Everyone in my class has been complaining about their now-tight scrub pants. I started out going to the gym every afternoon, but that fell by the wayside as my kids got sick and I fell behind in the reading. I couldn't face the prospect of failing the class because I'd taken the time to care for my body, so I didn't. I didn't fail and my body has the summer to get cared for.