Let's start at the beginning. You need to attend college, major in physics, have a high college GPA, earn high scores on the GED and physics GRE, and hopefully get some research experience. Then you apply to grad schools for astronomy, astrophysics, or physics PhD programs. That's another 4-8 years of college. Then you apply for jobs as an astrophysicist.
None of these jobs are easy to get. We produce more astrophysicists than we can hire, so many people work outside the field after earning a degree in the field. It's not easy to get a job as a college professor. Again, we produce more PhDs than we need to hire. Every job ad for a physicist or astronomer at a college will receive many hundreds of qualified applicants, and they'll only interview a few people. It's a very popular job with a starting salary average of $56,000 per year. Some schools pay more, most pay less.
You can start at any 4-year college or university offering a physics major. Your local state university is usually the best choice if you can get in; many have excellent programs. MIT accepts very few transfer students. That information is on their admissions website.