1) cause I’m into it 2) Cause I’m a firm believer in lil sister developing way too quickly for her age meanwhile mob being completely flat chested and not going through puberty until she’s like 17 or older, depends. I like to think mob would be a lil jealous of ritsu already looking more mature than her, and people mistaking ritsu as the older sister then mob. Also makes it great when mob does eventually hit puberty and changes completely, shocking everyone especially ritsu 😋