I dual boot Ubuntu and Windows, but could probably get away with a Windows VM, since I hardly use it. It's completely changed my perspective from "it's just the way it is" with Windows to being able to fix pretty much any big or small annoyance. If you're willing to spend the time researching and using those annoyances as opportunities to learn the OS, it's a good way to get your feet wet.
Like others have said though, if you want to start from scratch, I'd pick up a book on RHEL in order to learn command line basics, etc.
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