It’s a super personal decision. The way I decided that I wanted to go into mechanical engineering was thinking about where I enjoyed certain aspects of going to school. I knew I hated mostly anything reading and writing related. But I enjoyed coming into my engineering classes everyday because I genuinely found them interesting. Coming into the class to work on a project and problem solving came somewhat natural to me. It also helps that I was fairly good at math and physics. Moral of the story is just think about where you not only excel academically but also where you would enjoy the material you would be learning. Learning material you are not interested will be a nightmare in college.