Got for it - if you have the drive to get into Oxford and through the degree then, to be honest, I suspect the exact content of the course isn't that important. (I know very successful people who did degrees at Oxford in classics).

Actually, I personally would look on someone who does a music degree rather positively as it is the kind of course that only someone who has a passion for the subject is likely to do, rather than doing something purely for the career/earning prospects.