Shougakusei no Himitsu

Elementary school students are full of "firsts". Because they are in elementary school, they have all kinds of problems. They may feel nervous for the first time when they meet a boy they have known since childhood, or they may be confused by the sudden changes in their bodies......even friendships are hard to manage.....you can't tell anyone, but the truth is, everyone is worried about it. This is such a secret story.

(google translated)

Indonesian release by Elex Media as Rahasia Anak SD