If you become a physician, you can either actually treat sick patients or you can do research that might cure illnesses that haven't been cured yet. The other route is as a scientist, as people have mentioned. Either way you will need a bachelor's degree (4 year) first. One thing you could do now is try to get a position volunteering at either a hospital or research laboratory near you to see what the work is actually like. Research helps create great things, but often the actual work can be tedious. The trends right now are in artificial intelligence (AI), DNA/RNA sequencing, drug development, so the work might be very computer based or it could be in the lab doing things like pipetting and centrifuging. You can find videos on youtube like this one..
You will need a bachelor's degree at a minimum, during that process you can refine the scope of your interest. You may decide to apply to medical school, or pursue the PhD path. So, how do you ensure your undergraduate work will count towards a research program/opportunity? Seek foundational STEM courses rather than "survey" or familiarity type STEM courses. For example, avoid "survey of" or similar type science and math courses, opt for the full version (for example, "Principles of Chemistry", or "Microbiology I"). These "survey" type courses are great, however not always as accepted by all universities towards a STEM major or research opportunities. While taking these courses and their associated laboratory courses, you may often encounter various opportunities for professor-led student research, etc. This is a great opportunity to establish/expand your research skill set while building towards your path.
Volunteering at your local hospital is worth the time (and significant effort). You learn valuable concepts during volunteering and your ability to balance volunteering while taking undergraduate STEM courses is priceless.
Good luck and keep that interest alive!
My college did not offer a Pre-Med major, so I majored in Biology. Some of the courses I took include:
Anatomy & Physiology
Several of my classmates majored in Chemistry. They took most of the courses I took, but they also took Physical Chemistry whereas I took more specialized courses for my Biology major (Zoology, Botany, etc.).
I hope this will point you in the right direction.