Requirements

To be a critical care nurse you must have at least an Associate's degree in Nursing (2-3 years)

After your Associate's degree in Nursing you'll have to work in the basic hospital setting for at least 2 years before you can go to the I.C.U.

Some classes you can take as a high schooler are, intro to health science-health science 3, biology, anatomy, along with as many math courses as possible

Some college courses include advanced anatomy, micro biology, and of course your math courses