Principal Tony Membery said everyone at the school was devastated.
"There's a whole raft of emotions. This is raw, we're reeling.
"She's done well here ... it should have been her final year at school."
Her close friends and teachers had been told of her death on Wednesday, so that they didn't hear the news through social media.
Her death had taken its toll on the students, he said.
Guidance counsellors were being made available for those at the school.
"We know this is going to impact on people who knew her, beyond question. It's sudden, it's tragic.
"The kids were quiet and sombre."
She also worked part-time at Domino's in Te Awamutu.
A spokesperson for the company said they were "deeply saddened to hear of the death of one of our much loved team members [on Wednesday]."
"Her positive outlook and friendly personality will be missed.
"We would like to take this moment to express our sincere condolences to our team member's family and friends and ask that their privacy is respected at this difficult time."