Should I learn jQuery?

I do not recommend learning jQuery: In the past there were two major benefits of jQuery:

The syntax of plain javascript differed a lot between browsers and jQuery unified it.
jQuery made navigating in the DOM much easier.

However in the course of time plain javascript was improved a lot: Syntax is unique between browsers now and many functions making navigating in the DOM easy are available now, e. g. closest. Therefore these days the benefit of using jQuery is very limited.