Yes, having been a programmer decades ago I was amazed by the sheer volume of languages, libraries, frameworks, and supporting technologies involved. It can be overwhelming.
In theory you can build your software in a old text editor, like Notepad for Windows or whatever the Apple equivalent is. But there are also lots of free code editors, I’ve been enjoying Atom. Notepad++ is somewhere in between those. There are other good options.
If you’re just doing front end, that would just about do it. If you want backend, you’re going to need to install Node (and may need to for other things). For other languages you may need to download an IDE or two.
Github is pretty important. Yes, there are things to download for that and I find the Git Bash that I downloaded with that good for all the command line things.
But, if I may, I think you’re going about this backwards. Don’t worry about what you’re going to need in the future. Focus on what you’re doing now. You won’t know what you’re going to need in the future until you get there. Just add on what you need as you need it.
I’m guessing from your question that you’re not too deep into this. Are you working on the front end stuff? Maybe experiment with writing some stuff locally. You can use any text editor to create the files and run them in your browser. I also like to remind people that codepen will export your project to a zip that perfectly sets up all the files and directories.
Just take it as it comes. Worry about what’s in front of you. I think if you start worrying about what’s seven steps ahead as well, that you’re going to get even more overwhelmed. Those challenges will still be there when you get there, and you’ll be even better equipped to handle them.