Uncertainty on my Major

Hi, I am a junior in high school, who has a strong interest in engineering. Ever since I was young, I have always wanted to be a biomedical engineer. But I know that biomedical engineer is very hard to learn in college. I am interested in biomedical engineering and mechanical engineering. I actually have a reason that is personal to me for going into the biomedical engineering field, but the only reason why I want to go into the mechanical engineering field is because I excel in the core courses for that major. I do not even know for certain what a mechanical engineer does because mechanical engineering is so vague in itself. I also know that when writing the Common Application, it is better to have a personal reason to want to major in a certain field, which is the case for me in biomedical engineering. However, I do not have the courses for biomedical engineering in high school. And while the career seems interesting, I do not like biology itself. I also did not volunteer in any hospitals, so it shows that I am not as prepared as my other competitors would be. On the other hand, for mechanical engineering, I am more focused towards that field but I am not that interested in that field. I have taken physics, robotics, AP Chemistry, AP Calculus, AP Statistics, and I will take Multi-variable Calculus next year. I am not sure which major I should go with especially since I want to get accepted into a good school. While going to a top-tier college will be good for me, I also do not want to fail in college. Can I get some advice on my which major I should choose?

Mechanical engineers do go into some areas of biomedical engineering (e.g. design of prosthetics and other medical devices).

If you do not like biology, then is biomedical engineering really what you want to study?

High school preparation for any kind of engineering mainly consists of the usual well rounded based college prep curriculum, including coverage of all of the main sciences (particularly physics and chemistry, though also biology for biomedical engineering) and as strong a background in math as you can get.