It was Bill Gates who said that if you want to learn how to be a programmer, you do it by writing programs.
I was 15 when I created my own video game with C (compiled with Turbo C++ 3.0 even). It took me several months to complete because I was still unfamiliar with the language, had no real experience with planning out the project, etc. But I learned a lot from doing it. I also read just about every book I could find on the subject.
I would suggest writing code based on tutorials first to get an understanding of the basic C syntax and the functions that it uses. Pick up some books on programming that are more recent and relevant to today, and nothing that will teach you C "in 24 Hours!" or anything like that. Those kinds of books won't get into the finer points of what can make C a powerful language, such as appropriately using pointers and why they matter.
Pick up books and read articles about different algorithms as well. Algorithms are automated processes that make many programs actually useful and interesting.
Still one of my favorite books about programming in general is Code Complete, which is a bible of project development. There is a second edition of this one available that is even more up to date and relevant to usage today.
Also, read and use other people's source code for a variety of programs. They won't all compile with your type of environment, but you can still see how they operate. For example, Programmer's Heaven is a site that includes source code and executable files together for a range of applications in different languages; you can run a program that was compiled in the early 90's that will bounce a picture around on your screen, but because the development environments are so different today, you probably won't be able to compile that code exactly as it is. You can, however, still open it up and see how it works. And if you can compile it, you can tweak it and implement your own functions to get an even better idea of what it's doing.
This whole process will take at least several months before you can really do anything useful and it takes a level of dedication. But it can absolutely be worth it if you create programs that are both helpful to yourself and others and make them well-written and widely available. Just have fun with it :)