Looking back on it now, if I could do it all over again, I would've just started with NixOS.
I see people recommending NOT to make NixOS your first Linux distro, and I can't see where that advice is even coming from, frankly.
I've learned so much more about the inner workings of Linux systems, by using NixOS, than by any other means. I see no reason why that would be any less true if I'd never touched anything else.
I look at it like this: every other distribution, however ironically, hides the system by exposing it to the user directly; NixOS, however ironically, exposes the entirety of the system to the user by doing so at a high level of abstraction. Everything that happens on the system configured at the same level of abstraction; that is, there is no package manager properly: there is instead, if we're calling it what it actually is, a build system (that is for some reason, inexplicably) marketed as one.
It completely changes the entire concept of what having an operating system installed on your computer even means.
I honestly believe I would have a better understanding than I do now, now, had I simply jumped straight from Windows to NixOS and never bothered with anything else at any point.