Elementary School Student
Primary School Student, Elementary Schooler, Primary Schooler, Grade Schooler, Grade School Student
You know 学生 is student, so what is a small student? Think young. That would be an Elementary School Student.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
Both brothers are still elementary school students.
I've been playing basketball since I was an elementary schooler.
When I was in elementary school, the stone and the marbles were like my friends.