why choose python as your first programming language?
So far none of the answers have been particularly specific, so ill try to give a more specific answer.
The main benefit of python is that it is simple and fast to learn. it's fast to get something functional since the language automatically handles a lot of complexity for you (e.g. memory management) the most major downside of python is that its performance is lower than that of lower-level languages like C, C++, Rust, etc.
E.g. check out this short video for a side-by-side comparison of python vs Cvs assembly in terms of coding speed and processing speed https://www.youtube.com/watch?v=3PcIJKd1PKU
Do note that some libraries exist to give you C-like performance while still being python (e.g. numpy), which mitigates this issue for some applications. for example, most of data science/machine learning is done in python.
Also - there are a LOT of python libraries out there, so it's very easy to get started with a project and quickly prototype something.
Javascript is similar to python in that it is a high-level language, with not great performance but it's relatively fast to prototype things. one downside that it has (in my opinion) is that it is much more verbose than python, so you type more to write the same function.
But it's essentially obligatory for web dev. and thanks to things like node, its applications aren't solely limited to web dev. so you can consider it.
So, in summary, it depends on your goals.
If your goal is to become a full-fledged software dev, knowing python alone won't get you there (in fact, it likely won't help much). if you want to be in the machine learning/data science sphere, however, python will definitely be a useful skill for you. or, if you just like playing around with programming, then python is great!
If you want to get into web dev, javascript is a must. End of story.