The “Young Sheldon” star is unrecognizable in new selfies he posted on Instagram this week. He struck a pose in spectacles and wrote, “Incomprehensible drip from 1823.”InstagramArmitage was only about 8 years old when he landed the role of Sheldon Cooper in the “Big Bang Theory” spinoff “Young Sheldon”… now he’s 17! Getty ImagesFans couldn’t believe how much older he looks, writing, “When did he became so grown😭” and another wrote, “You're growing up too fast 🤧”Others saw some resemblance to another famous actor. “The next Tom Cruise,” wrote a fan, another agreed, “So handsome! Why do I see a bit of Tom Cruise from Top Gun here??