I need a similar word that may be used by a 6th grade girl; e.g.,“That kind of behavior is only appropriate for little girls of six or seven.”
It is not to tell her (may be used by), it is for her to write in her diary, something that she would say as an 11 year old—I doubt a girl that age would put such words in her diary—but I may be mistaken. In Spanish (my native language) "conducta apropiada" is common, and even younger kids would understand it, but using the above expression in their diaries may not be as common.