Continuity mistake: Missy's blond and blue-eyed like her mother, Mary, but in The Big Bang Theory, she's brown-haired and brown-eyed.
Continuity mistake: Younger Mary's a blond with blue eyes whereas on The Big Bang Theory she has brown hair and brown eyes.
Answer: It is shown numerous time in The Big Bang Theory and Young Sheldon that Georgir Jr is not the smartest kid going. They simply tell him Sheldon is getting a hair cut as it is believable. It's also shown that Sheldon has had the same style hair cut since he was 5. Since he is 9 in Young Sheldon, he's had the same style for over 4 years already. Easy to overlook that he hadn't actually had it cut after that long.
Ssiscool ★