That's just very impressive!
You really know your stuffs, as shown by how you draw in one go and without hesitation at all. The way you draw without sketch except the face while keeping everything neat, like the shadows, creases, perspectives, and colors is just wonderful. You have a great sense regarding those.
I think you definitely could become a great animator with that kind of skill.
also, it's nice to see some drawings done with traditional media as they're becoming less common due to digitalization trends.