If you are interested in pursuing astronomy or geophysics as a career a good starting place is to get an undergraduate degree. Undergraduate degrees in Physics with a focus on Astronomy or Geophysics topics, Earth Science, Environmental Geology, Astrophysics, Geology, Geoscience, Space Science, Planetary Science, Engineering etc. can help you build your career and provide a solid foundation. But which university is best for you?
Try to find a university that you like that has a good astronomy or geophysics department, with active research being done in areas that interest you. Staff supervise a research project that can count for a large fraction of the marks for the course, and can support you when you apply for the next stages of your career.
And be sure to visit universities on open days and for any students events they host!