Everyone says that we have to master C# for unity gaming. Is it easy?
Yeah, that should be fine.
Word of caution, though, the “JavaScript” that Unity uses isn’t quite the same as what you’ll see in web pages, if you’re coming out of that world. It’s close, but the little differences will add up.
My impression is that most amateurs use JS, and most professionals use C#. Personal preferences aside, it doesn’t really matter if you’re just getting started – the basic principles are the same in either langauge. If you’re going to be in this hobby for a while, your skills and knowledge will be useful no matter what languages you happen to know at the time.