Hi Kratos,
Cool you do physics. I do physical chemistry (I'm wrapping up year two of my Ph.D. right now).
My cousin sings jazz. She had a long history of gigs at good venues and a solid MySpace download history before putting together her first CD for sale. Strangers in Chicago had heard of her, and still her music generated very little revenue, even after quite a few years working the same scene (she's in her mid-thirties and is a nurse for her day job). At her CD release party, she was the headline act at one of the really standard, well-known live music venues in Chicago.
CDs have higher audio quality than mp3s and give the satisfaction of a tangible artifact with cool cover art, etc. The iTunes sales compete more directly with the freebies. I have trouble believing that a small-time musician, as opposed to a top 40 act, could generate a significant revenue stream with the online model. But that's an ignorant guess, so YMMV.
PLEASE don't spend money your parents are reluctant to part with. It isn't worth it. Until you have a loyal fan base, you are unlikely to make any revenue, much less profit. Their love and goodwill is the most valuable thing you have.
It sounds like you're a one person act, so I guess you'll need to record enough to be able to do live shows. To get material together to perform, my guess is that you'll need recurring access to recording capabilities, and the home recording route is the right one. Either that, or you'll need to get together a live band even if, like Trent Reznor, you ultimately put down every track of the recording yourself.
And learn your physics! I promise you that it will be much easier to pay the rent and put food on the table knowing physics than music. I had this same dilemma when I was your age and became a scientist, and I don't regret it. Physics is also a painfully competitive field, but it typically comes with a good training in math, computers, and quantitative reasoning, which make is short work to do all sorts of things - engineering, high-frequency trading at a hedge fund, etc.
Good luck!
