Group Chat is HuffPost’s weekly series about the joys and challenges of friendship, and how to reclaim our social lives in a busy world.

We’re lying in twin beds next to each other in a Holiday Inn hotel room. It is 67 days till my best friend gets married and we’re reminiscing about the time we went to a house party, aged 16, and someone turned the bath on and locked the bathroom door, leaving it to overflow. It flooded the floor and crashed through the ceiling into the room below. We cackle at the idea it ever actually happened in real life.

This is easily the hundredth time we’ve told this story to each other, filling in details the other misses along the way. Over the course of our friendship we’ve shared beds and stories countless times, sometimes with added laughter, shouting, hysterical giggles or tears. We know the other’s first kiss, first boyfriend, first love, first heartbreak; we’ve shared joys, regrets, and hangovers.

She has been my best friend since the day we sat next to each other in a year eight geography class. In two months she’ll walk down the aisle and have herself a husband – a new partner in crime. And although he won’t replace our friendship, it marks the beginning of a new chapter for us all.

Many of us in our twenties and thirties will go through a period of realisation where we understand that although we’ll carry many friends through life, those friendships will evolve. Especially when those friendships, like ours, have spanned decades of big life changes – new homes, marriage, children.

You’ll spend times apart and times together; you’ll go out into the world and meet new people. Some will stick around, others will be a fleeting footnote at the end of it all. But as you grow up, so the friendship grows up too.

Her new chapter as a wife, and they hope soon to be as parents, won’t stop our friendship but it will change it.

I’ll no longer be the first person she calls with good news, like when she found out she had the GCSE results she needed to get into college. No longer the person who helps her with the buttons on another vintage dress we never should have bought. No longer the person she rings when she’s scared about walking home along that bit of the bypass where we were both flashed that half-term. No longer the person who spends endless summer days just lying in the park, sharing discount M&S sandwiches and texting boys because we had nothing else we needed to do. 

As someone who deals heavily in nostalgia I feel a degree of sadness in realising that the past is now exactly that – the past. The future looks different. 

But although our priorities will change, the amount of time we can spend with each other lessens, and life weighs heavier as adult responsibilities come to bear, our friendship will remain the foundation under it all. We might not be the same as we were, but we’ll always have us.

I’ll always be the person she drags to the dance floor when Marvin Gaye ‘Ain’t No Mountain High Enough’ starts to play. I’ll always be the person who helped her clean the kitchen floor before her mum came home (after yet another house party we weren’t meant to have). I’ll always be the person she texted first thing after meeting her future husband. And I’ll always be the one who climbed over the garden wall with her after that bath started overflowing.

We might not have walked down the aisle together but we’ll always be each other’s first love.