As a new mother, it was both extremely exciting and extremely nerve-wracking when my first born daughter started pre-primary.
She would be attending a school in Perth's northern beaches - a school that drew families in from Duncraig, Padbury, Marmion, Hillarys and Sorrento. As a result, it soon became clear to me that the school was divided as such.
You either rolled up at the kiss-and-drive in a BMW, or you parked your 1996 Holden where it couldn't be seen.
I was perhaps a bit naive that my daughter wouldn't feel the effects of the mild socio-economic divide, but at the same time I had to admit I was slightly unnerved by the material wealth of her school friends.
We weren't dirt poor, just ordinary. In fact, I distinctly remember my daughter's Christmas wishes that year: a pool and a staircase because she desperately wanted the two-storey house all her school friends had.
Even so, she eventually became quite friendly with another little girl, Samantha, and was often invited for plays.
We often reciprocated and I don't think either of the girls ever remarked on the difference in their houses or which suburb they lived in; and there was quite a difference between Samantha's beachside villa and our modest inner suburb home.
Eventually, Samantha's birthday came around and my daughter came home with the invite in her book bag. It was a Hungry Jack's party, and she was thrilled. She didn't get takeaway very often.
At first I was a little surprised; I thought Samantha's parents would have quite a large, lavish affair.
Instead I pushed the thought aside and rang Samantha's mum to accept the invitation. That would probably have been the end of it, but I asked her what Samantha might like as a present.
Her mum said not to worry too much about a present - she would be getting heaps anyway as she had invited most of the class.
I laughed and said that I didn't know Hungry Jacks was that big.
Soon, I learnt it actually wasn't. I had heard whispers from other mothers about attending a party at Samantha's house, and began to put two and two together.
I worked out that my daughter had been invited to only one of the parties - the smaller party. I also found out us 'other' mums were referred to as the 'Glengarry group' - that is, the group without the BMWs, the boats or the mortgages set to last over the next fifty years and beyond.
The other party Samantha's mum had organised was the large one where she would get all of her presents, and it was set to be held in their beautiful, pristine home. Of course, us Glengarry mob couldn't be trusted with all the white furniture and marble counter-tops.
After a little bit of undercover-mum detective work, I found that this party was reserved for the Sorrento, Marmion and Hillarys kids.
If I hadn't already told my daughter about the party I would have told Samantha's mother where to put her invitation.
Instead, I coldly thanked her for the invite and my daughter went along to slum it with a bunch of kids who ended up being some of her best friends in years to come. The level of snobbery at play stunned me.
Earlier this month, I read about how a little girl had invited all her friends to her ninth birthday party. She invited 12 friends, and received only two RSVPs. It was beautiful to see how the Perth community opened their hearts to her and her mother, but it was a perfect example of how 'birthday party politics' can really affect how your child understands socialising and friendships.
For kids in primary schools, birthday parties are the number one way of socialising with their peers in large groups, outside of a classroom. An invitation to a birthday party is not just an invite to celebrate someone's special day, but an invite for a child to get to know their peers. It's supposed to be a time of inclusion, making friends and laughs.
The 'Glengarry Group' incident was almost 20 years ago, and while it was a weird type of segregation rather than exclusion, it had the same effect on the children involved. It drew a line between children based on what it was their parents had, and who their parents wanted to socialise with. It stopped them from being able to socialise freely, and with whoever they wanted.
Mia's story reminded me of the Glengarry Group, and how I felt back in 1998: isolated, embarrassed and completely in shock that somehow my social standing affected my daughter's friendships. It felt like I had stopped my daughter from socialising freely because of what other parents thought of me.
But as the years have gone by, I've grown to learn it isn't up to us as parents to dictate and determine the friendships of our children.
My youngest daughter is now 15-years-old and is attempting navigate the new generation of parents determined to forge their own social groups and impose them on their children. I have told her to keep her head high and be kind, but I can see her struggling to understand why she wasn't invited to a boat cruise, a concert or a shopping trip. It can be heartbreaking.
All I can say to those parents is the same advice I give her: be kind. Try your best to pick up the phone and RSVP, make sure your kid isn't being a bully and let them determine if they want to make friends with the kid who's family doesn't own a boat.