I was able to write decent "C with classes" code pretty early on. It took quite a while before I realized that wasn't the best way to go about things.
Ditto for me. Most of my "C++" experience is in embeded avionoics, which is really "C with classes". After 12 years, I still don't consider myself a master, but I can code just about any type of app efficiently.
As I said, the language is a tool. Mastery is a mindset.
Truer words have rarely been spoken.