Completed Python “Basics”, is it proper to head straight to learning Matplotlib, Pandas, etc.

As the title states, I’ve completed the basic concepts of python, I have some background in C++ so it was a fairly easy switch.

However, I would like to venture out into backtesting and probability models.

Which libraries do you suggest I learn first? Also, do you learn libraries like you learn the language? — the documentations seem very vague to me.