When you're just starting out, it probably doesn't matter too much. Pick one, and pick a project to build using it. You'll learn lots no matter what language out framework you use, and most of that knowledge will be portable to other back end languages and frameworks.
Maybe do something like building yourself a personal Pinboard clone. Or your own personal Twitter clone. Or anything else you'd like. Deliberately just focus on bare bones functionality. No fancy extras.
And no JavaScript. Make sure your project works without it. You can add in JS later in if you really want to, but worrying about it now will just take your focus away from developing back end development skills.
Maybe do something like building yourself a personal Pinboard clone. Or your own personal Twitter clone. Or anything else you'd like. Deliberately just focus on bare bones functionality. No fancy extras.
And no JavaScript. Make sure your project works without it. You can add in JS later in if you really want to, but worrying about it now will just take your focus away from developing back end development skills.