Her daughter Mia was born three and a half years ago and she also has three children from a previous relationship.
The couple met online more than a decade ago and originally said having more kids wasn't on the cards for either of them.
Mrs Cooper told Nine's A Current Affair program that "it's never too late to be a Mum".
"I actually breezed through it," Mrs Cooper said of her pregnancy. "I didn't have any problems."
"You're only as old as you feel. I will always stand by my kids."
Mrs Cooper is one of the oldest Australian women to fall pregnant using her own eggs.
Anthea Burns, now 60, gave birth to her son Nick in 2011, at age 55. He is now six years old.
Mrs Burns and her husband Pete, 60, never expected they would become parents. They met later in life and both agreed that having children wasn't for them.
"I just thought I was too old," Mrs Burns told news.com.au last year.
Doctors advised the couple they didn't need to use contraception, because of their age and Mr Burns's low sperm count meant the chances of falling pregnant were two million to one.
The chances of her successfully carrying a child to term were even lower - seven million to one. But soon Mrs Burns realised she had fallen pregnant naturally.
"We were advised by both our GP and our obstetrician to terminate the pregnancy. We had to give it some serious consideration, but Pete was stronger than I was and felt really blessed," she said.
"Now I look at Nick and he's such a gorgeous, healthy boy. It's so nice. Can he chuck a tantrum in Coles? Of course. But he's a very sweet kid."
On Monday, Today Show host Lisa Wilkinson warned women approaching 40 not to wait to fall pregnant thinking they will be able to have children.
Her comments came after designer Camilla Franks dismissed medical advice she received to pursue fertility treatment as "wrong" and "absolute BS".
Franks, 41, is currently expecting her first child, which was conceived naturally.
In August, a 62-year-old Tasmanian woman became Australia's oldest mother after giving birth to a daughter conceived via IVF. Her partner is 78 years old.
At the time, AMA president Dr Michael Gannon labelled the couple's decision as "madness", "selfish" and "wrong".
An Indian couple in their 70s celebrated the arrival of their first child in May, almost 47 years after getting married.
Daljinder Kaur, 72 and Mohinder Singh Gill, 79, made headlines around the world - and were also labelled selfish - for their decision to receive IVF treatment so late in life.
There's a long list of female celebrities aged 40 and over who have fallen pregnant.
There's Janet Jackson (49), Michelle Bridges (44), Kelly Preston and Geena Davis (both 48), Halle Berry (46) and David Bowie's wife Iman (45).
Many of these women have used younger, donor eggs.
