Name for idea that if a concept is confusing you then you are starting to understand it

This is an interesting philosophical question.

I'm not sure if this is super helpful, but it reminded me of Bloom's taxonomy. As you ascend the learning hierarchy, you sometimes find you have more questions, but that really serves to prove you are gaining a deeper understanding of the subject.

It's not a single term, but it might explain the process you're describing.

https://en.wikipedia.org/wiki/Bloom's_taxonomy

I also tend to say, "You don't know what you don't know." I use that when people ask, "If you didn't understand, why didn't you ask for clarification?" And I say, "Well, I didn't know that I didn't understand!" I guess it sounds like nonsense, but sort of implies that you only have real questions when you start to understand. Ignorance is bliss, as they say.