Well girl puber earlier than boy so yeah
!!!! Not at 6 or 7!!!!!!! WTH??? I know there are cases of girls getting their period at like 11 and those are incredibly rare cases but 6 or 7??? Cmon bruh. No. And if we’re talking about magic growth as a cause to their physical growth, then the MC should look like he’s 17 or 21 because of how much power he was able to accumulate and still growing. He surpassed his dad. So I won’t take “magic” as a possibility. She was successfully able to draw the MC as a kid at that age(5/6) right after he trained with that dragon and received the beastwill ...so it’s strange she wasn’t able to draw the sister properly looking like her age.
Does her little sister look like his age now? She should be 6 years younger than him so around 6-7 years old yet she is as tall as him? Weird.