It's generally understood that when a hero debuts in their own solo film, it's going to be an origin story. Granted, there have been exceptions in the past, particularly in Zack Synder films, where he foregoes the traditional origin story and opts for a few intercut flashback sequences. In the Marvel Universe, though, the traditional method is typically favored, and Captain Marvel will be no different.
Marvel Studios President Kevin Feige addressed the subject at a recent 15-minute preview screening of Doctor Strange (via Cinema Blend), where he compared Captain Marvel to the newly introduced Black Panther.
"[Black] Panther is not really an origin story, since we saw him already in Civil War. But his standalone certainly introduces you to 99% of his world that you never saw. And Captain Marvel is certainly an origin. It's an origin story from the start."
The character will likely make her debut in the upcoming Avengers: Infinity War, a tidbit that directors Anthony and Joe Russo accidentally revealed at a special Smithsonian Institute panel. They referred to her by name, and when asked if that was confirmation, they replied "Um...Captain Barvel. Totally different character." Suffice it to say no one bought Russo's explanation.
It's unknown if she will actually get her powers in Infinity War, or if they'll just use it as a way to introduce fans to the character. Either way, the major character progression won't happen until her solo feature, and fans are eager to see what actress Brie Larson can do with the popular character.
Captain Marvel hits theaters on March 8, 2019.