You were part of class 3-E and you all were trying to kill your teacher Koro-sensei. Koro-sensei builded a pool for the class and walked there with you all.

Koro-sensei was annoying everyone with the whistle. But he eventually stopped.

You were walking over to the pool. Usually, you don’t wear the school uniform and often wear baggy clothes, so seeing you in a bikini, shook everyone.