Assessment of progress

So I want to be a great tester.
I'm building up a syllabus of material to learn, and a way of tracking my progress against that.
How though do I know how good I am at actual testing?
It's not like there are formal assessments that can tell me how I'm doing, I have no colleagues that are more experienced than me, so their insights are going to be limited. So I can critically review work that I have done, with a view to what else I could have tried. What does that look like though, what are the actual steps I'd take?
I could apply the Socratic method and see in which piece of work I can see better ways to think about it, and approach it. I think this has a limited use to me currently as without broader and deeper experiences in testing, I may be unable to have an effective socratic conversation.
I think I have to build myself a self assessment model, definitely not a strong suit of mine.
I'd be reviewing heuristics used, where they the best, could better ones have been used, and what of the oracles, were they good enough, could alternative ones been found that would have given a better insight into the rightness of what I was testing.
Ideas from others who have tried a similar thing would be most welcome.