Not too sure about all of that.
Yes, python is very popular nowadays, but mostly due to machine learning, not so much in terms of web development I think. Most of the web is still powered by PHP.
I can also tell you Facebook was not written in python but first in PHP and later in Hack (their custom evolution of PHP). Google and YouTube mostly use Go as their language of choice.
I would recommend just trying to compare some of the languages, find some tutorials for example, and see which one clicks with you most.