After high school it takes about 4 years of university to become a registered nurse.
After time spent working as a nurse, including 2 years of critical care, one can apply to CRNA school, which takes an additional 2-3 years.
Hi. What is the specific career you are looking to go into? I see alot of tags on this however I do not see anything specific as to what you are going into. It would be a little better to give you ideas to think about if you were a bit more specific as to what you are looking to go into.