But what's perhaps surprising is that, until she was 17, Fiona was an only child to a single mum.

She grew up in a tiny family by comparison to her rambunctious, exuberant brood she now wrangles across the ACT and two states.

And the family of 11 is unusual in a nation where a household of 2.6 people [statistically speaking] is the norm.

Raised in regional NSW, Fiona says she was 17 when her brother was born.

"Before then, it was just me and my mother," she said. "I spent a lot of time reading books. It was lonely.

"I think it probably wasn't an accident that I went on to have a big family.

"But I don't think I would have had six - or nine - if James and I hadn't met."

Fiona and her husband, James, are a modern Brady Bunch, amped up a little.

She brought her three children to the relationship; he brought his three. And then they had three more together.

So for the record, there's James' children Jessica, now 25, who has her own son Hudson, 1; his daughter Merinda, 22, who has a three-year-old son Taylem; and Shannon, 20.

Fiona had Rachel, now 22; Gus, 20; and Abby, 18.

Together, the couple had Olivia, 11, Matilda, nine, and Eddie, six.

But that's just the formalities. There are really no lines of delineation when it comes to their kids. They are all theirs.

It was a kind of slow burn relationship for Fiona and James.

"We knew each other as teenagers and used to hang out at the Dickson Tradies but weren't overly aware of each other," Fiona said.

They went on to have their own, separate relationships until years later when Rachel and Merinda both attended the same school and became best friends.

Both separated by then, James and Fiona started off simply as parents organising their girls for play dates, birthday parties and sleepovers.

They got together about 12 years ago. And they and all the kids started living together, with up to eight children in the house at the same time.

What could have been a stressful transition, turned out not to be.

"We don't have the stereotypical relationship," Fiona said.

"James does all the cooking. He had been a single dad who had his kids 50-50 so he knew how to look after them.

"I think my parenting definitely improved when James and I got together, We really complement each other. He's probably the more maternal person, he really is. Whereas if the kids fall over, I'm the one who'll say, "Get up, you're okay, toughen up'.

"We do kind of play good cop and bad cop, but at different times."

She doesn't want to put her kids in cotton wool. She feels her younger children are more resilient because she has given them more free rein.

"I'm more relaxed because I don't overreact and kind of cruise more now," she said.

"I was probably tougher on myself with the first three because I wanted them to be perfect and I eventually realised letting them be themselves is perfect."

Fiona says her own parenting was informed by her own mother, who remains interstate, living overseas for half the year. They are not close and Fiona wanted something different for herself and her children. They are a family who likes to have fun and laugh and not take life too seriously.

She was 21 when she had her first child.

"I didn't think I was young. I thought I was a woman. I thought I was all grown up. In retrospect, I was still a kid," she said.

James was an electrician by trade and Fiona had a successful online children's clothing label, Flossie.

When the couple opened Markets Wanniassa in March, as an outlet for artisans and craftspeople across Canberra, James left his job to work full-time in the shop. Fiona is out the back and James is the front person of the operation.

"We actually get along better the more time we spend with each other," she said.

"And then we tag team. We're in all of this together."

They are now also "Nan" and "Pop" to their two grandchildren.

"It's pretty cool," she said.

"We don't stress as much. We feed them up with lollies. We're the good ones. And the nice thing is, they have all these young aunts and uncles to play with."

So the best and worst thing about being a mum?

"The best is watching each child grow into their own self and finding their passions," she said.

"Butt even better than that is laughing and joking and being silly together, we have so many family puns and jokes we need a Lester dictionary.

"When your kids say, 'I love you', that's actually pretty awesome too, especially when they're all grown up and still say it. Actually, probably my biggest favourite is watching each of the kids develop connections with each other, and seeing how close they are and look out for each other, that's when you know you've done an okay job.

"The worst bit is countless 'poonami' nappy changes," she laughed.

"And the sibling fights over the dumbest things ('She looked at me, stop looking at me' or 'She has the red plate, I want the red plate" - you know the ones!) Absolute worst bit is the teen years, you know they're trying to find their way and dealing with hormones and loads of other crappy stuff, but they're so horrible some days you've gotta look at their baby photos to remember how much you love them!

"And nits.. we hate nits."

Fiona says she has strong advice for any new mother.

"Be easy on yourself," she said.

"Don't have such high expectations [about what a mother should be].

"I reckon with my second lot, they know I have interests and a life and that I'm a person separate to them. And I think that does them good.

"To my older ones, I'm just a mum. And even the older ones say, 'We wished we had of known more about that'. Who I was and what I liked."

Mother's Day will be a time to just enjoy the kids; although this year they will be in the shop for at least part of the day.

"I just get completely spoilt," Fiona said.

"I wake up with breakfast, a zillion presents they've made at school. And I always get slippers."