Another example of Dawson casting in the HP movies is Moaning Myrtle who is a 12 or 13 year old character played by a woman who in 2002 was 37. Since the character is a ghost who won’t age, they needed someone who wouldn’t visibly age over the length of the movie series, and that’s easier to do with a young looking adult actress.
Sissy Spacek in Carrie may not have been 15, but she certainly looked like it.
No it isn’t. Dawson casting is casting people obviously too old for the roles they’re playing.
But the OP is looking for justified examples.
Oooooooo. Okay, yeah.
How about Don’t Tell Mom the Babysitter’s Dead? At age 20, Christina Applegate didn’t really look 17, but she looked about right as someone trying to make herself look old enough to get an adult job.
In the musical Once Upon a Mattress the character of Princess Winifred seems to be written as a tomboy. But Carol Burnett was 26 when the play premiered on Broadway. Young enough for the physical demands, but past the tomboy stage. The part was later played by an older-than-Burnett Dody Goodman and the still-older Imogene Coca, and the tomboy gradually became more of an old maid.
The Curious Case of Benjamin Button? Both main characters age throughout the film, albeit in different directions. The majority of the time, they are playing characters much younger or much older than themselves.
The oddest thing to me is that, when they finally are playing their actual ages, they actually look pretty young.