You basically said you don’t want a path that is too difficult or stressful, that you don’t want to study all the time, and want a life. A double major of science and major is very difficult and even scheduling can be rough (labs versus rehearsals).
Some of the folks on here have kids who have careers in music or in academic music or went on to other fields or other studies. In my area there is an ensemble made up of doctors who all majored in music 
In this day and age of high tuitions and costly loans, it is understandable that parents are nervous. I know many music majors at this point and they have all done well, whether in music or not in music. Perhaps someone in your community or at school or a music teacher can reassure your parents. Or at least discuss it with them.
If you do a BA in music you can still have lessons and performance, but have room in your schedule for some science classes. Maybe that is a good compromise. Or do a BM and then do post grad (post-bacc) work for med school prerequ’s. Or maybe at that point you will have other plans.
For a double degree to work financially, you could look into merit scholarships or state universities (SUNY’s are relatively affordable even for out of staters). There is a thread from the past dealing with merit scholarships. Maybe someone else can refer you to that thread.