C was first developed in the early ’70s, and despite it being over forty years old, it’s still widely used. But C is also the basis of other languages, most notably C++ and C#. Windows for example, is programmed using a combination of C and C++.
Learning C is the ideal first programming language to learn. The chances are that once you’ve mastered C, you’ll move onto C++ or Java or some other language, and probably hardly ever code in C again. But because so many other languages are based on C, you’ll find moving to them very easy. Even web scripting languages like PHP and JavaScript share a similar syntax to C.