Regarding C, my first language was C and I've always been thankful for that. It helped me understand low-level programming, memory management, pointers, registers, etc. It also helped me better understand how my computer's hardware works. Having C as my first language also gave me a greater appreciation for languages that handle all that complexity for me.
Regarding Python vs. Scheme, I like both languages. I tend to prefer Python for certain types of programming, like NLP, machine learning, and math, just because the available libraries are so good. Having said that, I feel that the functional paradigm is superior to procedural programming and definitely (for me anyway) better than OOP, so for everything else I'd choose Scheme or some other functional language, like Elixir, Elm, Haskell, or Erlang, depending on my mood and what I'm doing.