Teaching at the college level is often done by adjuncts these days, and the arts/humanities are areas of study that are declining, not growing. I know doctoral grads who are struggling to support themselves or not even working in the field.
I think your best bet is to major in science and continue lessons and do extracurricular performance. You can also take music electives. You can still go to grad school for music if you develop along that path.
But you are a sophomore. Now you know more about what is ahead and what you need to work on or think about, so enjoy high school and things will become clearer when you actually have to apply.