Newsflash: Time flies. We all bemoan, "I'm so old" (even when we're really young), but one thing that never fails to make us feel, well, old? When you realize that an actor or actress you've watched playing one of your favorite childhood characters as a kid is all grown up now. Over here at J-14, we've covered Disney Channel girls who look totally different now and then-and-now photos of your favorite Nickelodeon guys, but these are child stars who are currently teenagers, although they looked so fetus the way we remember them in our minds.

Even though it's been years since these stars played kids in their most iconic roles, it is still sometimes difficult to wrap our minds around the fact. You were shocked to see Mackenzie Foy's transformation from Renesmee Cullen in Twilight to the now-teenage actress, and she's not the only child star who is now a teenager. Surprise!

From 13-year-old Francesca Capaldi to 19-year-old Zachary Gordon from Diary of a Wimpy Kid, get ready to feel ancient. Or decrepit. RIP me to the depths of my soul. Click through the gallery to discover which child stars are actually teenagers now. Can you believe it?