From age five, they were in love. It was meet-the-teacher night, and school hadn’t even started yet. We meandered through the hallways and classrooms of the school we’d chosen, hoping for Spanish immersion and IB education. They were the two oldest daughters of three siblings, and they chatted, did cartwheels, and were holding hands before the night was over.

Her tall and slender, long-lashed mother quietly commented, “You see? They’re already best friends.”

And so, nine years later, when I texted my daughter to make room in her drawers and space in her bed for a loooong sleepover, her only, immediate, obvious response was, “REALLY!!!!!! OMG THIS IS AMAZING!!!!”

Because when you’re in love, when you have a connection, it does not matter if six extra people are going to live in a house built for… five?

Because when you make a fast friend at age five, when emotions are so visceral and honest, it’s probably something worth cherishing.

Because when you have a bonus-five-bedroom dream house, why not share the dream?

Because if the situation were reversed, wouldn’t we all, minute by minute, hand in hand, reach out and make the world just slightly better, one soul, one family at a time?

Because what makes a family?

Girl Scouts. Trials and tribulations. Cookie selling. Lost money. Lost causes. Frustrations. And so much fun you would laugh until you nearly peed your pants, all in the snow on a bitter cold January night. Bridging ceremonies, brownies, a baby brother in tow on camping trips.

Backyard barbecues. Eating meat or not eating it. Sharing our sad stories. Telling the truths we were never able to tell in the schoolyard, at our jobs, in our “real lives,” but that slid so easily from our mouths in the comfort of our back patio.

Camping trips. Sharing pies and drinks and a bite of an ice-cold river. And again, laughing until we cried under a hazy moon and starlit sky.

Sleepovers. Girls screaming into the night, little brothers trying to keep up and eating two giant waffles before ten a.m., before they were even ten years old.

School. The daily ins and outs, friends come and gone, field days and jumping into the sky as if you were jumping right up into heaven. Teachers we loved and hated and commiserated. Our shared experience.

Family parties. Little girls in pretty dresses pretending to drink tea. Everyone, kids and parents, gathering household items to make a Halloween-happy costume. Parents gathering in the kitchen to catch the scene and capture a moment of each other’s joy, each other’s sadness. The connection found in youth, in young parenthood, in the heavy task of raising young people to become wise people.

Because… from the age of five, they were in love. Look how they’ve grown. Look at the young women they have become. Look at the family they have made for themselves.

That is why we can add six people to our five-person house. Because from age five, these girls have carried us into the home we call home. It began with a smile, a cartwheel, a hug.

That, and rearranging some beds, is about all it takes.