I wouldn’t say one had to master a particular area first.
Just to clarify, that’s not what I said and I’m not suggesting it at all.
Now you don’t have to be an expert in each. But do try to pick one and have it mastered.
I’ll agree everyone has different styles of learning. But one thing that’s known is if one is focused on one particular thing, one has better chance of understanding it. You may think multitasking is the way to go. But scientific research says otherwise. Now a lot of these topics are intertwined, so learning, for example HTML and CSS at the same time seems logical. But jumping into WordPress without clearly understanding how to structure sound HTML/CSS, seems detrimental to anyone’s progress.
Just to reiterate, I’m not saying for anyone to be expert in one or more things, to be able to move onto something else. I would say, if you have working knowledge, then move on.
Hope that helps.