Why is "learning Linux" such a stressful experience .. for a
or for anyone-else?
Frankly, I think it is because:
You have to do potentially-irreversible things to your present configuration. You are (justifiably) fearful of getting into a situation you can't back out of, and putting your data at risk.
My strong, emphatic suggestion, therefore, is this:
start learning Linux on another machine. Leave your primary war-horse exactly as it is, without touching anything or repartitioning anything. "Another" computer, such as the one you still have lying-around after upgrading to the machine you're using now, has the great advantage that
it doesn't have anything of importance on it to 'screw up.'" 
(And if it does, just take the hard-drive out and put in a new/new-to-you one, completely blank.)
(It does help if the unit has a USB-port. If it doesn't, a dandy USB2.0+Firewire card costs about $50.) Having
two disk drives is handy, too. They don't have to be large or fast, or new.
At this point, pop in a CD-ROM containing the Linux "distro" of your choice and install it... stock, vanilla, untouched. Then,
play with it.
Put a legal-pad and a box of sharpened pencils (yes, pencils) next to the computer and keep a diary. When you encounter something that you don't understand, a question you'd like to ask or a new discovery you'd like to explore,
write it down. Once you've done that, you know that you won't forget it: and now you can
decide when to re-approach the issue. You can
choose whether to chase after this particular rabbit now, or later. When you find the answer,
write the answer down too.
To start with, the "distro" does pretty-much everything
for you, and you can spend your time noodling around to figure out just what it
did. A little later on, when you're feeling more adventurous, you can start "really changing things." And if it all collapses in a heap around you ... so to speak ... "so what?" On
this machine, you can simply reinstall and keep noodling.
This is vastly superior, imho, to "dual-booting."
In time, when you are
much more comfortable with Linux, you can explore that topic again, but this is just not a good way for a
to start out. You have enough on your plate, learning Linux, to justify
risking .. well, anything at all .. as you do so.
If you don't have a spare computer lying around, look at used-computer shops or even a Goodwill store... Huge amounts of perfectly-good but slightly-used computer equipment is literally
thrown away every single day. Most of it is
dandy for learning Linux.
For what it's worth, this technique is also good for any sort of testing situation, or for validation of any sort where you need to be
certain that what you are doing is not affected by, and is not affecting, anything else.
One final suggestion ...
take it slowly. You can only absorb so much at one time, and some days will be much better than others. This is one of the reasons for the diary. This is also a good reason for having your favorite game (on the other, un-touched computer), maybe a good physical game of tennis, maybe a nice book, reconnect-with-the-spouse, or whatever, to
balance your learning-experience. Periodically you
will feel that your mind is exploding.
But at least your prized data and the computer that it's sitting on won't be at risk.
