I would agree with those who tell you to learn lathe and mill work first. I am a journeyman tool and die maker. I can't tell you how many times I've bailed out gunsmiths who only learned their machining the "monkey see, monkey do" way in gunsmithing school and didn't know what to do when things went wrong or they made a mistake. Also when they took on jobs that demanded machining skills and knowledge beyond their learning.
With regard to learning the business aspects of it, yes. A "hobby" that makes a profit is a business. A "business" that doesn't make a profit is a failure. There are a lot of places to learn how to run a small business and how to make a viable business plan. Find one.
