Ms Ashby, the most seriously injured of the four, is still recovering from a broken ankle, broken femur, broken radius, degloved knee and nerve palsy, which means she can't use her left hand until nerves grow back.
She might be "broken" on the outside, but her determination is strong and she is looking forward to walking again within about four months.
"Doctors said I should have been dead not from my fractures but from my internal injuries. I was in the operating theatre for eight hours the first time and the amount of blood lost was huge.
"I was determined to get better for my kids and they are the ones who pulled me through."
On December 2 last year, Ms Ashby and the kids were heading to a fish and chip shop in Taupo about 7.30pm.
Troy Thomas' time in hospital. PHOTOS/SUPPLIED
They had just taken the twins to shooting lessons to learn firearms safety, something they thought was important after the death of Reporoa 11-year-old Connor Phillips in a hunting accident two months earlier.
On a straight on the Napier-Taupo Rd a driver in a car coming the other way crossed the centre line and crashed into them, with Ms Ashby's driver's side taking the impact.
The last thing Ms Ashby remembers was Michaela saying, "look at this idiot".
"I then woke up and there was a guy there and I was asking him to cut my seatbelt because I couldn't breathe."
In a crumbled heap trapped underneath the dashboard, she turned her head to look for the kids.
"I could only see Luke ... I was just hoping the kids were okay but I could only hear two of them. They were in shock and pain. Bystanders were assuring me the kids were safe."
Ms Ashby managed to give a rescuer the phone number of the twins' father, Kelvin Thomas, before blacking out again.
The twins were airlifted by the Westpac Rescue Helicopter to Waikato Hospital and Ms Ashby and Michaela were airlifted to Rotorua Hospital by the BayTrust Rescue Helicopter.
Because they were split up, family members were not sure which hospital to go to.
Ms Ashby said the next few weeks were a scary time, with her and Luke's injuries nearly costing them their lives because of complications.
But after two weeks the boys were released from hospital, Michaela was released after two-and-a-half weeks and Ms Ashby was released after a month. She lived with her sister in Rotorua for three months before moving out to Reporoa to be closer to the boys, who were living with their father.
Ms Ashby needs more surgery and is still in a wheelchair as her ankle recovers but doctors say she should be back to full fitness by summer.
She admits there had been some dark periods during the past six months, including watching her kids in pain and being told by her doctors she couldn't walk for a while.
Christmas was also a time of reflection and being thankful they were all alive.
She said their families and the Reporoa community had been amazing, and Michaela in particular had stepped up to help her Mum.
She joked she had gone from being a "terrible teenager" to a lovely mother figure.
The woman in the car which crossed the centre line pleaded guilty to four counts of careless driving causing injury last week. She will appear in the Taupo District Court for sentencing on June 21.
Ms Ashby said the police asked if they wanted to take part in restorative justice and meet the woman.
"We didn't really want to do that. There's still a bit of grief and anger there so we asked she pay reparation and make a donation to the rescue helicopters instead."
