First, you can major in music and still go to medical school. I read, a few years ago, that music majors have the highest admit rate to medical school at 62%. Sorry I cannot cite it- lost the link. But you get the idea. Of course you have to do prerequisites, either during undergrad or after graduating. There are post-bac programs for that (see Goucher’s as an example, there are many such programs.)
Second, please read the Double Degree Dilemma essay posted on the top of this music forum, for a description of the different ways to study music. There are many paths for undergrad, and some go to grad school as well.
-BM in a conservatory or school of music, freestanding or part of a college/university (you usually need to submit materials for prescreening including a recording/video, then also, if passed, do auditions).
-BA in a college or university, with varying degrees of performance in the curriculum plus extracurricular performance; usually lessons are available, often for credit, and credit may be given for performance as well, but not always. (Some have auditions for admission, some have auditions for participation in extracurricular music; for application you would include a music supplement with recording, music resume, letters of recommendation from teachers/directors.)
Both BM and BA will have theory and aural skills, music history, ethnomusicology/world music, composition, music technology and so on. The BA is more academic and will often include distribution requirements )if you combine music and science, find a school with lower or no gen eds). A BM is 2/3 - 3/4 music classes and a BA is 1/4-1/3 music classes.
Other options are a minor in music, a double major with music and something else, a double degree with a BA and BM or sometimes a BA and MM. Double degrees are 5 years.
There are exceptional individuals who major in something other than music, continue lessons and performance on and off campus, and continue to progress enough to enter grad school or a career in music.
You CAN major in anything and still enter one of those “safe” jobs. Colleges are not vocational in that sense. You do NOT have to do a premed program, or prelaw, or whatever it is your parents want. It sounds like you do not yet know what you want to do after college but have a desire to pursue music for 4 years and see how it goes. I hope you can convince your parents, but that is my personal opinion.
Perhaps showing them the Double Degree Dilemma will help. David Lane, who write it, was admissions director at Peabody (part of Johns Hopkins) for decades and knows his stuff. Good luck!