How to be an astrophysicist? For a high-school students, what are the ways to become an astrophysicist?

What should he/she take in college?

What is the career path to become an astrophysicist?
Different education systems differ, however

At school you would take maths and physics courses, at least covering calculus.

As an undergraduate, taking (or majoring in) physics. Also probably doing some more maths and perhaps some astrophysics courses. 

As a postgraduate doing Masters study in astrophysics leading to PhD research in astrophysics.  By now you could say that you are an astrophysicist.

Then working at a university or similar institute. 

This makes it all sound easy, but I think I should add a warning. Getting a permanent (research) position at a university or similar institute in astronomy is highly competitive, and to get there takes a combination of hard work, high competence, high motivation, and luck. Many highly competent people end up moving out of astronomy and use their skills elsewhere, for the simple reason that society does not spend enough money on astronomy to employ all highly competent people who want to spend their life on astronomy.