I envy your delicious coloring skills! Meanwhile I have to offer this critique: her expression is less "contented introvert" and more ... I dunno, scheming? I think her irises and pupils could stand to be bigger and "cuter." Still, this is a great picture.
I just wanted to draw her face more calm and relaxed, but thank you for your critique it's nice to read something different than "Nice" or "it's sucks". I like to know what people like or dislike in my pictures . I need advices to become a better artist so thank you again, I will remeber this, when I will want to draw Fluttershy again