C is a good general purpose language but it isn't for beginners. I'd recommend learning to write scripts in Python first then move on to C.
Are you going to be using a PC first and then moving on to the Amiga? If so the PC version of Python is
here and the classic Amiga version is
here. Finally the textbook to help you learn Python is online:
How to Think Like a Computer Scientist: Programming with Python as either a web page or a .PDF file.
If you'd rather start out in C++ the textbook for that is
How to Think Like a Computer Scientist: Programming with C++. But be sure to get the C++ Standard Template Library before using this book as it needs it badly.