Linux is the core of an operating system made by Linus Torvalds. And no, Linux isn't an extremely
complex operating system that requires an extremely good knowledge of computers to use. Actually, Linux is easier to use than Windows. Linux is Open Source, witch gives it huge advantages over Windows. For example on Linux you have much more choice than on Windows. There are loads of Linux distributions (distros) from which you can choose each having different features, desktop environments etc. Why are there so much Linux distros? Because, as said above, Linux is Open Source. So that means that anyone can edit the source code, create new distros etc. Even you can !
At first it may seem complex to choose a distro but the point is that there is no one choosing what distro you should use. Linux is also more stable. There are MUCH less viruses because it is Open Source. Because if no one can see the source code well no one can find patches for security problems and we will find out that there is a security problem only when it's too late and there is a massive virus or hack. Linux is also less buggy and there are also no blue screens of death (R.I.P Windows 8). Also, Linux is free both in terms of cost and software. You don't have to pay 100 or more bucks just to get an OS. You can even game on Linux ! (OK it has a little bit less performance than on Windows but we don't really care). It is actually better to game on Linux because you have more choice than on Windows and having more choices is why PC Gaming exists (Some games even run faster on Linux than on Windows with the Vulkan API)
Just one last thing : Linux is everywhere. Nearly all supercomputers run Linux. Nearly all the internet is powered by Linux. Android phones and even the Librem 5 Phone runs Linux. Linux is on Raspberry Pi's. Loads of connected objects run Linux. Even the ISS runs Linux!There are also loads of other stuff that run Linux.
To resume, Linux is Open Source, Free, more stable, leaves more choice and lastly is much better than Windows and this is Why I Use Linux.
If you think I forgot to say something or if you have any questions important feel free to tell me in the comments!