You can make it as simple or complex as you'd want it to be.
I'd also suggest choosing C++ instead, if you'd want to stay close to C, but it could be really any language as such games wouldn't be too demanding.
Think about it first. Collect your thoughts.
What would a typical user interaction be like?
- User choosing options pre-defined (e.g. a, b, c,)
- or perhaps User entering text and the game trying to parse it and make sense of it (e.g. "go to door" or "pick up the sword" or "hit enemy with the sword")
- Or something else?
How would the story unfold?
- Would this be a linear experience?
- Would the user be able to choose various paths (both physical and story paths)
- Would there be any story at all?
You should consider these and other questions to define the basic behaviour of your game before you start to code.
Good luck!