I feel comfortable calling myself an Amateur Blacksmith. I think it serves as a fairly universal disclaimer as well as concedes to my much more experienced peers that I understand my seniority. That said, if I made a living doing it, I would consider myself a blacksmith, by trade.
Should I take courses, apprenticeship, etc, I assume it would come with some kind of prefix. Similar to "Professional Engineer" or "Licensed Electrician", or "Journeyman Blacksmith". Without some kind of sanctioning body to bestow such a prefix upon me, I would never feel right calling myself such.
Regardless, personally I don't put much weight behind such standards or earned prefixes beyond the fact that the possessor of such completed whatever was required of him/her to receive it. Almost universally, to earn any degree or prefix of any kind one must do specifically what they are told to by their teachers and success is nearly a guarantee. Performing a learned task or say, calculating a learned set of equations, speaks volumes about what you can do when given direction, but nothing about what you can do on your own. For the most part all any prefix or suffix does is tell potential clients, customers, and employers that should you choose to be a good worker, you can perform well as part of their team.
"You can send a man to college, but you cannot make him think"
Should I have the means or time or opportunity to pursue any formal education in blacksmithing, I would jump at the chance, primarily for the education. The titles themselves will mean little to the people I'd like to work with or for, I'd still have to put up or shut up.
What does speak volumes about somebody is the caliber of their work, but again, this is subjective. In the end the only earthly judge who matters is the one signing the front of your check, be that your employer, customer, or client.
All that said, there are a few very popular members of the smithing community who personally stick out to me as people who will have had a great impact on the craft and will continue to have a large impact even after they are done, and I don't know their official titles or prefixes or even how they all make their livings, and they range in age from not legal to drive in some states to legal to retire twice anywhere, and what makes them special is not their work (while it is often stunning), but their teachings. Without them, I wouldn't have even known where to start.
Steve