The Paige Young Sheldon character has been a prominent part of the show, but Sheldon never mentioned her in The Big Bang Theory. This inconsistency has been criticized by fans who wonder why. It's possible that Sheldon intentionally kept Paige's existence a secret because he didn't want his friends to know there was someone with comparable intellect who didn't struggle socially. Paige and Sheldon's relationship has been complicated, and she causes complications for him emotionally. She returned in season 6 of Young Sheldon, and her story remains dark and disturbing. It's possible that Sheldon saw Paige as a tragic tale and didn't want to bring her up.