Carol Danvers has been a C-list character in Marvel Comics for most of her 50-year history. Only within the past seven years has she held the mantle of Captain Marvel that sells her as a pretty big addition to the Marvel Cinematic Universe.
Danvers has a convoluted comic book history, one that surely made her difficult to distill into something simpler for a movie. Yet like Tony Stark before her, the lack of a signature storyline made Danvers a blank slate for Marvel Studios and the five writers (including Guardians of the Galaxy's Nicole Perlman and Inside Out's Meg LaFauve) who took a crack at Captain Marvel's story.
A comic book overhaul in 2012 by writer Kelly Sue DeConnick (who appropriately has a quick cameo in the movie) made Danvers a tougher, more accessible character fueled by all of the doubts and obstacles encountered throughout her life. That perseverance is what pushed her into becoming an elite fighter pilot and gave her the edge to stand as an equal with Captain America, Iron Man, and the other Avengers.