Elementary School Student, Primary School Student
noun
You know 学生 is student, so what is a small student? Think young. That would be an Elementary School Student.
しょうがくせい
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.
その兄弟は、まだ二人とも小学生です。
Both brothers are still elementary school students.
小学生の時から、ずっとバスケットボールをしています。
I've been playing basketball since I was an elementary schooler.
小学生の時、石ころとビー玉は、友人みたいなものでした。
When I was in elementary school, the stone and the marbles were like my friends.