This is a network that cut its superhero chops on casting a 24-year-old as a 15-year-old.
Heck, they were doing that in the '50s. Jack Larson was 24 when he started playing the teenaged Jimmy Olsen in Adventures of Superman -- and as you may recall, there was an episode called "The Boy Who Hated Superman" in which the titular "boy" was played by a 29-year-old actor. Burt Ward was 21 when he started playing Robin, but Robin wasn't old enough to drive until the third season, so the character must've been around 14 when the series started.
I believe Andrew Garfield was 47 when he played teenager Peter Parker.