When you get ready to
actually try Linux, I suggest that you use a
"virtual machine" on your existing system – which will not "change" at all.
My "go-to favorite" is
VirtualBox®, which is full-featured, easy to use, "runs on everything," is supported by the largest software corporation on the planet, and is
absolutely free. It's certainly not the only "virtual machine monitor" that is available, but IMHO it is a very good one and likely to be your best choice in this use-case.
Now, you can
experiment with an
actual Linux installation to your heart's content, without disrupting anything on the "host" computer or putting anything at risk. While the "guest" operating system can discover that it
is running in a virtual environment, it cannot directly see nor affect the "host." The VM's "hard drives" are actually ordinary files on the host system which grow and shrink as required. Linux is now running in a window (which you can of course make "full screen"), and it will actually run almost as fast (on modern CPU's) than it would on "bare iron." Now, the task of "getting to know Linux" is safe and painless.
FYI: Today, all of the "production" Linux environments that I use daily as a consultant
are "virtual." I have dozens of them now, all different, which I "spin up" or "spin down" as required.
Given this flexibility, I'd suggest that you download
any distro's "installation CD image" and basically
jump in! :) The water's fine and you cannot drown. You are not putting anything "at risk." You can even "snapshot" your VM image and restore it. Fully
expect to "suddenly feel lost," and bring your many questions here. Be patient with yourself: you are
learning.