She had no history of medical problems.
However, in the last four to six weeks McEldowney had noticed Mia seemed a little clumsy.
"We started noticing she was banging into things more and falling down - we thought it was general clumsiness or that she wasn't concentrating," McEldowney said.
"Then on Saturday in Mackay, we had a netball game and her coach - who is also my sister - voiced her own concerns about Mia, which mirrored what we had been thinking."
It led the family to take Mia to hospital. Doctors quickly ordered an emergency MRI scan.
It picked up a mass on Mia's brain and the next morning the family was sent to Brisbane on an emergency flight.
McEldowney and her husband remained hopeful, but further investigation revealed the tumour was on Mia's brain stem, and that it had spread.
Doctors said they wouldn't be able to cut it out and without treatment Mia was given nine months to live.
McEldowney and her husband were completely blindsided.
Mia will now begin radiation therapy in a few weeks that may reduce the size of her tumour and prolong her life by two to five years. But the therapy alone won't save her.
"We are hopeful that if we can prolong it for long enough, there might be something in the future that can help," McEldowney said.
For her part, Mia is yet to fully understand why family and friends have rushed from around New Zealand and Australia to visit her.
"She just thinks everyone wants to come see her," McEldowney said.
The family are trying to remain positive and keep Mia informed on what to expect with the treatment.
They are set to spend an extended period living in Brisbane away from their home in Mackay and a Givealittle page set up to help them has raised more than $27,600.
McEldowney said that while Mia could have been born with her tumour and there was nothing she could have done to prevent it - it was a reminder to other parents.
"If you have any concerns or notice anything in your child - no matter how small or stupid you might think it is - get it checked," she said.
