I think you are adopting a very sensible and practical approach to learning about ZC before you commit yourself to a working (real) webshop.
All the while this "test" shop is on your local computer, you can make as many mistakes as you like - as no actual (real) sales will be affected, and no (real) customers will be made angry!
The point is this:
You really only need to have zencart version 1.3.8a - and if you run ONE or even ONE HUNDRED installations, they should all be operating on the latest version.
In a couple of weeks' time, after you have developed a better understanding of how ZC works, you may feel confident enough to MOVE your webshop to an internet server to start online trading.
Only you will know when you are ready for this - and the process will no doubt involve working with the book and visiting the forum for tips and tricks.
But when you are ready for a real, live shop, MOVING it to an internet server is quite straight-forward and there are lots of FAQ, tutorials and advice posts on this website.
Naturally, if you come up against obstacles, then submit a post and people will help.
One piece of advice...
When you decide to go live, please consider choosing a host that has good zencart knowledge, and who has configured their hosting environment to accommodate zencart.
There is a link to "certified hosts" at the top of this web page.