It doesn't really take long to get the basic stuff figured out though, but there is definitely that initial feeling of being lost. As others have suggested, start out running something in a VM on your Windows desktop, then you can quickly go back and forth to practice doing things in linux as you have time (plus it's a huge benefit to have a working browser in Windows so you can do a search if something breaks).

Linux has a number of different desktop environments to choose from, and what's cool is you can load up multiple types and select one at the login screen. If you want to start with something that is reasonably comfortable, try loading the 'Mate' desktop. Maybe I'm just used to old-school Windows (Win2K was the last one I used), but I've always thought Mate did a good job of putting all everything in logical places. As for the OS itself, there's also been a lot of suggestions so I'll throw mine in as well... I'm a die-hard Debian fan, both on my desktop and on my servers. It does NOT push bleeding-edge releases on you, so this means you won't have the very latest updates but to me it's more important to have a rock-solid system that I can always rely on. I've been using it for about 15 years now and it has never failed me.