And when you start a BSc at the earliest, you are something like 20 years old? (16 when you apprentice, 19 when you finish that, one more year plus two tests to enter university?)
20ish sounds about right - in Switzerland, men loose a year due to military/civil service.
To be honest, I find the idea of classifying people from journeyman to master rather unsuitable for today's knowledge work. It does not pass the smell-test for gate-keeping.
What you need to know changes every five years. Call someone grand-master of software engineering, sure, but no matter how great they are they'll not get your CRUD database UI done any faster - if their career was all about signal processing for particle accelerators and medical device certification. More likely, they'll over-engineer and over-spec and not be prepared for requirements to change completely after a year, or for sinking several days into CSS layout issues. Beyond a certain baseline of experience (say, working five years in the field or so), what counts is knowing the domain well (interpreting what the customer wants). Or already having experience with the technology that applies to problem-of-the-day. Or being highly motivated to learn it.
It's not like crafting with wood. The nature of wood doesn't change every six months. The tools we use to work wood don't change every six months.