How old is the cute Hotaru in Sailor Moon?

Xiaoying is bigger than Xiaotu!

In the comics, Little Rabbit always called Xiaoying "Sister Xiaoying"

But after Xiaoying was reborn, she became as big as Little Rabbit. At that stage, Grade 3 of elementary school. But in fact, Xiao Xiaotu looks like a child, but his actual age is 900 years old. Because of the power of the silver crystal, he will not grow up~

In the animation, Xiaoying is a student in the first grade of junior high school, 12 and 13 years old. Years old. Little Rabbit is a primary school student, in grade 2, 7 or 8 years old~