Start anywhere, being interested in it is all you need (and a decent search engine, and learning how to describe the problems you have to the search engine). Whatever you do, I think it's a good idea to pick something that will be your project on Linux so that you have a concrete goal that makes Linux useful.

For hardware I'm a cheapskate so I recommend using whatever you already have, but I'm sure others here will point you in the right direction 😹

I recommend dual booting at first with grub, so it's more of a departure from windows. Using a VM like Virtualbox or Hyper-V is a bit safer and easier, but you're probably not interested in Linux for safety or ease of use.

We're lucky to live in a time where if all you have is a Linux tty (no gui, just a text mode shell) you still usually have a phone with Internet to look for help. It's a good exercise when you have the time to try and get the system back up in those situations without external help for at least a few minutes. Most distros still install manpages just for times like these (man and info commands view them)