I'm not a luthier, but am self-employed working in a similar area (amps!).
Some random observations:
1) All the luthiers I know enjoy what they do, and like "not working for the man". I don't know any who are making vast sums of money, which would suggest it's quite a competitive market.
2) Whilst becoming self employed has it advantages, you need to do your maths right, ie you need to work out how much you will need to charge to make a living.
3) You need to decide what you want to aspire to: do you want to work on guitars as a hobby, as a second source of income, or as a full-time job?
I started out fixing/ building amps as a hobby, which then became a part time business interest, and finally my full-time job. Thus I was able to build up a customer base and business reputation before relying on the business as my sole source of income.
4) Many of the luthiers I know have had some form of formal training, eg Leeds College of music etc, and all seem to have worked for/with other luthiers to gain experience before becoming self-employed. A sensible course of action would be to do a luthiery course and decide if you like the work. If you show an aptitude for it then, then you might consider trying to get a job with a reputable luthier to gain experience. This will probably be poorly paid, but in my view good experience is invaluable.
Good luck!