How to choose a major properly? Is there a way be sure it is the one?

I'm a senior high school student. I love biology, and math (other science subjects are intersting for me but not fascinating like the ones above). Right now I`m thinking between medicine and biomedical engineering.

Anatomy out of all biology topics interests me the most. But I`m also a fan of Math and I think there is not much of it when beeing a doctor.

On the other hand, BME is much more unclear for me and not that defined. I`ve read the descriptions and different field they work in, but I`m still not sure if it`s that promising for the future, while being a doctor is clearly shown everywhere to be a great job, with great output.

I`d like to know how the insides work in BME, and if there is a way to know if i`ll be interested in it. Would be greatful for any feedback from people working in these fields.