C# is one of the best and easiest programming language out there at the moment, it works great on most platforms, great for creating games, software, web APIs and a whole lot more.

The .NET framework is being updated every once and then provide more features and feasibility.

For a place to learn: https://www.thenewboston.com/

You can create iOS, Android and Windows Phone apps using C# via Xamarin.
Create games with C# using Unity. And applications are easily made with VS no matter what language.
If you use MonoDevelop, you can also create Mac applications.

One of the pros is that the syntax is similar to Javascript, Java, C++ and others, so in case you want to learn another language, it will be really easy after you understand the syntax's concepts. (Unlike Python, Lua or other languages make it hard to keep up with its syntax)