I have a LA and the learning curve was sooo much more than I ever dreamed . I have had mine about 4 years and one thing I know is that most everyones experience is different, probably from area to area. So many LA's say they have a 6 month or more backlog but I honestly wonder about that. That would mean they are storing possibly 100 quilts or more before they get to them. I don't know anyone who has that much room or insurance to cover them if they had a fire. The truth actually may be that they only want to do so many quilts a month, so if they have a dozen or so steady customers, thats all they need. If they take extras, they are not in any hurry to get them done.
I practiced at least a year before I would take paying customers. My first year of doing it as a business,I had maybe 12 quilts. I have a fairly steady business now but the first of the year was dead. So its a good thing I am not making payments on it.
One thing that hasn't been mentioned is the physical side. It is hard work. Hard on your legs and feet and back. That needs to be an important consideration. Also to get started, you have an investment in your LA as well as thread,needles,insurance,patterns,classes and batting,maybe? You definitely don't have time to sew for yourself like you want and if you get a top done, you are last on the list to get it quilted. I agree with the suggestion to buy a used machine and try it before you invest in a more expensive new machine. While it sounds like fun, there are sure a lot of days, I have to push myself. Its a job. And you have to treat it as such.