Well, my piano teacher is a pretty well known indie musician (well, depends on if you are into her genre, anyway)..and I'll tell you what she does b/c musicians have a high rate of failure like acting (maybe you can think in terms of acting? idk trying to help)...
She teachers kids on the side, goes into elementary schools and gives talks about being a musician, schedules own gigs, produces own cds (basically cutting out expensive "middle man"/agent of being a musician) until she got signed. She also has a friend who makes a lot of money doing accompaniment as a musician.
so maybe you could tutor kids (your colleges are pretty good haa) on the side (make big $$$)...get a job at like a movie theatre (not glamorous but you could do that at night and go to auditions in the day)
if you want to convince your parents, you just need to have a well-thought plan