A beginner shouldn't begin with a language just because it's "fast".
C isn't fast because "it's just fast", it just gives you finer control over the program, which can be faster or it can be even slower than Python , depending on the implementation.
It makes sense to start with Python, I think. It removes all the low level concept confusion (stuff like pointers,types casting, memory allocation etc.) and makes you focus on just the simple stuff.
One can always move on to C later, and even combine C and Python, and I think that's going to be much more productive than starting with C.