Internet on a XP system, that's brave to be sure
More like 600 to nearly 1,000 different distros or builds anymore
Linux anymore is more or less like using Windows. Long gone are the hours of running commands to get things installed. Hell, they have a built-in feature that would equate to the Microsoft Store now on most, if not all, distros
(Distros like Puppy Linux not withstanding) Honestly, I never fooled with Commodore or Amiga PCs. I did DOS ages ago but have forgotten most if not all, of it.
But yeah, Linux is more or less an easy OS to use anymore, unless you're going for Arch
(By the way).
Arch It isn't ungodly hard but not very user friendly, to be sure. I would try something simple at first, like Linux Mint or Peppermint OS, maybe even Zorin or Kubuntu.
Fun fact: You can run Linux off a USB drive to try it out. It will work fully, albeit a touch slower than it would if fully installed, but not enough to make that large of a difference.