There is no required curriculum in high school for any profession. You goal now is to make sure you graduate high school with the best grades you can get. You will have to attend a college/university after high school to get the training you need. Good luck!
It could be helpful to find out from the nursing programs you're interested in applying to which prerequisite classes would be required for application, and start from there. Many nursing programs typically require anatomy and physiology, introductory psychology, statistics, etc. and they vary from school to school, which is why it could save you a lot of time to look at the specific required prerequisite classes for each nursing program.
Elizabeth recommends the following next steps: