I want to create a Progressive Web App but I am kinda new with Web development, I understand Java Script is a Client Side Language while Python is Server Side.
What do you recommend me to create a Progressive Web App? What are the good and bad things of each option? For example if I PWA is created and a lot of peope uses it, would there be any difference in efficiency, speed, etc. if I use one language or another?
Django is written in Python and is a great framework for your backend logic.
When it comes to PWA, you are basically stuck with using Javascript and a framework like React.
Facebook, Airbnb and Uber all uses React and they still manage to scale and stay efficient. So to answer your question on using languages for scalability and efficiency, it depends.
Also, I don't think that you should worry to much about scalability issues at the moment. Just go with some frameworks and tools which you think is interesting. If you one day have scalability issues, oh boy, you should be lucky! That means that you ha a lot of customers using your product and if the business model is right, you should then have no issues scaling in the right way.
Django and React are awesome tools for building PWAs, and there is a great need for those competence as well. So, dig in and let them show you the way!
Happy coding!