The apprenticeship for Medieval bowyers was 7 years. I believe a modern Journeyman has the same apprenticeship? Seems about right to me. I didn't feel comfortable with bow making until I'd been doing it on a regular basis for about 4 or 5 years. I didn't really feel like a 'bowyer' until somebody asked me to make them a custom bow. At that point, I felt like what I was doing was good enough that a complete stranger was willing to part with their hard earned money for it. I also felt more like a bowyer after I stopped counting how many bows I'd made.
It's subjective. Anyone can call themselves whatever they'd like... who am I to judge? But, the above criteria is what I feel I need to call myself a bowyer. I think 'bowyer' is maybe like 'welder.' I have a nice Lincoln MIG welder, and I can weld, but I'm not a welder. I have a buddy who is a welder, and he doesn't think I'm a welder either!
Early on in this journey, I was a bow maker. Now I feel like I've earned the title of bowyer. However, to each his own!