When the first show in the universe is built around the idea of 5-years worth of flashbacks, then it should come as no surprise when one of the Arrowverse series starts casting younger versions of their regular characters. Arrow was all about the flashback for five seasons and Supergirl did an almost entire flashback episode earlier this year. Legends of Tomorrow time travel and have come across a few younger and older versions of themselves and we have seen the younger Jefferson Pierce (Cress Williams) watch Tobias Whale (Marvin 'Krondon' Jones III) kill his father. And while the Flash has done a few flashbacks, it looks like they'll be diving into the past of Caitlin Snow (Danielle Panabaker) soon.
EW.com is reporting that Victoria Askounis has been cast to play young Catlin in an upcoming episode of the series. Askounis appears to be a newcomer with no credits that I can find. Not much is known about Caitlin's past other than her mother, Carla Tannhauser (Susan Walters), is a bit overbearing and cares more about her work than her daughter. We haven't met nor gotten a name for her father yet but he is believed to be deceased.
Caitlin was introduced in the pilot episode of the series and was not a metahuman until after Barry (Grant Gustin) went back to try and save his mother causing the Flashpoint Paradox at the beginning of season 3. Killer Frost, her alter ego, was introduced on Earth-2 first and then the Earth-1 Caitlin discovered her powers over time after Barry tried to fix what he had done.
The Flash airs Tuesdays at 8 PM on the CW.