One of the blessing and challenges we have in the data wrangling world is that there's a cornucopia of tools. You can't master everything, there's not enough time. So figure out what you need to know, (broad knowledge), and what you need to know well, (specialization). Hopefully these coincide with talents and passions.

If you really want to learn R or Python, realize that R is a stats language and Python is a  general programming/scripting language with lots of good data/stats libraries. There are decent books that teach statistics and the each language in conjunction. As a data janitor and programmer, I find Python much more useful.

As for me, I have to temper my infinite curiosity of technology, science and history. So I stay current or slightly ahead of the curve for the career/job and delve into more fulfilling science and math passions outside of work.