小中高生 しょうちゅうこうせいじゃなかったです
shōchū kōseijanakattadesu

Noun
Desu Copula

The polite, past negative form of 小中高生

1. Was not a student (elementary, middle, or high school); Was not a schoolchild.

Past/Perfective
Negative
Polite
Casual Register