The final decision is yours but I was in the same situation many years ago. I started to do research work before university and I also wanted to be a researcher.
First, I chose Med School, however I realized that wasn't my cup of tea at all. When I started it, I didn't realize that I have to go through many practical courses. In my country you study anatomy on corpses fixed with formalin (I heard that it's rare in other countries). And the worst was I had no time for research at all because I had to study all the time, something which was far from me.
So I left it after one year, then did my bachelor's in time, and now I am preparing for my final exam to finish my master's and I recently published a first author paper in a D1 journal. So for me the Med School option was not the right choice, but I can't emphasize enough that my career path is unique in many aspects.
Among my acquaintances, people who start Med School with ambitions like "I will be a researcher not a doctor" then choose the medical career as a doctor. They have much less time for research and they have to take part in practices which bring them closer to the medical career and push them far from the basic research.
However, working as a doctor always will be a stable and honored profession. Working in basic research either with an MD or with an MSc degree is very challenging and competitive. And years after your PhD, you will be able to live a slightly calmer a life and get a normal salary but the way is cragged and you can fail easily.
Many people won't agree with me, but my personal opinion is that doing Med School is unnecessary if you definitely want to be a researcher because MD prepare for you how to care with patients and identify and treat their health problems instead of built the basis of the skills which are essential for being a good researcher.
So I love my career path and I am happy with my decision, but you choose this way if you feel you are highly dedicated to be a researcher.