A young horse was in an unexpected location, got spooked, and kicked the girl, briefly knocking her out.
"She was face down ... covered in blood everywhere," Maddison's mum told NZME News Service.
Although the girl sustained a broken jaw, fractured sinus, lost many of her teeth and needed stitches, Maddison's family were counting their blessings.
"The doctor says she's lucky to be here."
A doctor told the family if Maddison had been kicked "just slightly higher" she would have been in a potentially deadly situation.
"She's pretty tough ... just taking it all in her stride," Ms Smith said. "It could've been worse."
Although Maddison was still recovering from surgery after the ordeal, she'd already voiced a desire to go showjumping as soon as possible.
"She's meant to be competing on Sunday in Papatoetoe. She asked her dad last night if she could still go and compete," Ms Smith said. "She's quite an incredible little girl."
Although the surgery was extensive, Ms Smith said her girl was as chipper as possible.
"She looks like Maddi, she's just got lots of stitches."
Staff at Starlight Farm, where the accident happened, were also said to be impressed with Maddison's bravery.
Maddison's mentor Tina Fagan said it was an "extremely unfortunate accident" that happened when Maddison darted into a shed out of the rain directly "behind a young horse standing where a horse doesn't normally stand in front of the stables".
Ms Fagan said on Facebook the girl had impressed her with "her strength and resilience".
The Auckland Rescue Helicopter Trust flew Maddison and her mum to Middlemore and crew members also praised the girl for her courage.