Re: Have I sold out?
I don't think it's an issue. If the regular job allows you to indulge your hobbies then I see no harm in that. It's a case of making informed financial decisions. If the band starts making serious money, then treat it seriously and eventually you may very well be able to cut some of your employment commitments. Without a family and with the age you are, I can see no harm in that provided that you are able to get another job if the band doesn't work out.
Really, if you are pursuing music as your sole source of income then you have to take what you can when you can. There are many professional musicians working on a regular level that have very long and varied back catalogues. Weighing up what is important is the key. Stability and guaranteed income or a big risk and instability.