Make sure you are on a college academic track. Different states offer different educational high school academic paths for students. Make sure you take the classes that you will need to be admitted to a college with a nursing program. You will need to take higher level math and science classes.
Learn study, organizational, and test taking skills now. In order to successfully make it through nursing school you will need excellent academic habits while being self-disciplined. There will be few academic challenges in life as difficult as successfully making it through nursing school and passing your NCLEX-RN exam.