Kristi and her friends Lavinia Marra, 17, Stevie Ward, 18, Kim-E Maguire, 17, Jess Jackson, 18, and Ngawaea Taia, 16, called themselves "The Pretty Boys".
Karen watched three of the tight group of friends Lavinia, Stevie and Kim-E put on identical but different-coloured dresses to the one her daughter would have worn - the one she was laid to rest in last month - while Jess chose a peach-coloured gown. Ngawaea was attending a pre-ball event elsewhere.
A month ago, Kristi and four other students were driving to Tauranga to get supplies for the ball. The car crossed the centre line and collided with another vehicle.
Kristi died the following day in Waikato Hospital. The other girls in the car were also injured and one, Tui Martin, 19, is still there in a critical condition.
Dressing for the ball Lavinia, Stevie, and Kim-E remembered the day they found out Kristi wasn't coming back.
The girls heard about the crash by text message from one of the injured girls.
"We thought they were sweet because she was [only] talking about the car being messed up," said Lavinia. "But then one of our teachers got a call at school and found out about it and just left the room. She said something like 'what do you mean they're in hospital?' and just walked out."
When the girls eventually found out their friends were in Rotorua Hospital - before two were helicoptered to Waikato - they headed to the emergency department.
"We said we were there to see Kristi and they told us we'd have to go to the ICU," said Stevie. "Someone said to us 'We're really sorry girls, but this isn't the place to be'. There were so many people there. I thought she was [already] dead."
Kim-E was in Auckland. "I felt helpless. It was weird. I just wanted to be there."
The girls watched as Kristi was transported to Hamilton and followed her up by car to say their final goodbyes.
"The hospital goodbye was the hardest," said Kim-E. "My whole body felt numb."
Jess said: "It was so hard knowing she was going to die, knowing they were going to turn her life support off. We had a silent trip home.
"It was hard for me today. Me and Lavinia had all our appointments [for hair and makeup] with Kristi today. We were all supposed to be together. It felt wrong being there. She was supposed to be there, too."
Lavinia said "The Pretty Boys" still haven't come to terms with the fact that Kristi is gone. "It sometimes hits me, that she's really gone. Then sometimes it just feels like she's on holiday."
Karen, who said she normally received 100 text messages every day from her daughter telling her she loved her, misses those texts. Kristi's friends text her every day instead to try to make up for her absence.
Karen said she knows her life has changed forever and while she's tried to be strong, for everyone, but the ball preparations yesterday were hard.
"Today has been emotional," she said from Lavinia's living room. "She would have wanted me to be a part of today though. She wouldn't have wanted everyone else's lives to stop.
"If she were here, she'd be having pre-ball drinks at home. She would have had her makeup and hair done with the girls. This ball was 'the thing'. The only thing that gets me through is knowing how positive Kristi was about stuff. She wouldn't want anything to stop and she wouldn't want me to be crying now.
" She was not just my daughter, she was my best friend. I told her stuff that no one else would know. I am so hugely proud of her."
Karen said she was so happy to see Kristi's friends had decided to get new ball dresses made after she died - matching the one she planned to wear and was buried in.
She said she still has happy moments when she thinks about Kristi but it's been tough.
"I don't get my 100 texts a day. I don't sit in the house and watch Kristi flying in the door then fly out again. I don't get called to say she's locked her keys in the car and needs me to come pick her up."
The school plans to build a playground in Kristi's name, and is having a tree planting on Wednesday in her honour. She will also receive a graduation certificate at the end of the year for her family to keep.
