The first tang of autumn is in the air, but there is a lingering summer stretch in the evenings, and we watch through Dad's vast curtainless windows as the last remnants of light fade to black. Our local landmark, a prehistoric passage grave, lurks in the shadows of the night, but even when it's invisible, its energy pulses around us, its essence indefinable, wild, something that belongs to us and our youth. Even when we're gone, I feel like our presence will haunt this place, because it is here that we are truly ourselves. A shiver with a hint of anticipation passes through me as I stare out the window, contemplating the future. This is a turning moment for us all and it's time to get the party rolling.

Tully hands me a bottle of champagne, with the smile that's been appearing on the covers of teen magazines all summer long. "Hope it's not too much?"

Scrutinising the label, I shake my head. Tully is famous now and I can't get used to it. Somehow, it feels – wrong. Nobody could ever have predicted Tully, the clueless, eager-to-please, new guy, could suddenly become a rockstar, but when Four came back to Ireland from London two days ago, it was an event that took us all by surprise. The whole country was caught up in it. Interviews on the radio, pictures in the papers, even a segment on their arrival in Dublin airport on the 9 o'clock news.

"Don't worry," I say, "Veuve Cliquot is never too much!"

Spike roots through my music collection while I open the bottle with a slow firm twist of my wrist the way Dad showed me. The cork makes a discreet pop and a slight hiss as it comes out and I fill the glasses without spilling a drop. If you pop the cork with your thumbs, you waste the champagne because it explodes all over the place. Of course, according to Dad, if it's Prosecco or some cheap shit, you should totally pop the cork.

"Okay," I pass around three of Dad's cut crystal flutes, keeping hold of the fourth for myself, "we've waited a long time for this. Isn't it amazing? We've all got what we want. I'm going to art college, Kit is joining Spike in Trinity and Tully has got his music."

We laugh as we raise our glasses. "To us!"

"I love you guys, you bring me down to earth." Tully puts his arm around Kit and pulls her in closer. "You've no idea how much I've missed this, all of us here together, chilling."

She snuggles up happily, gazing at him adoringly. "It's like old times."

It's cute, I guess, but it's not like old times. This place is not my home. Home was the house that was here before, the house Dad described as a shitty bungalow and tore down to build the in-your-face-Axel-Carr version with sharp angles and vast expanses of glass. Still, I can't help smiling, as I pick up my champagne and let myself sink into the massive leather couch beside Spike.

The only time I ever really appreciate Dad's house in the Irish countryside is when I come back from staying with Mum in London. My mother rules her space like a queen. Her home in Kensington is small and immaculate and she shares it with Andrew, the youngest and most uptight of my three older brothers. When I'm in London, I get the spare room and all the temporary vibes that go with it.

This summer I was there for the whole of July and August, instead of the usual three weeks in June. After two months with my mother, it's liberating to be back home with Dad who's generous with his space. He never makes me feel like I don't belong here and doesn't mind me filling his house with my friends.

"Tully's career is taking off, and you guys are finished school, about to embark on something new, but nothing has really changed for me," Spike's voice is plaintive.

"Untrue," Kit protests. "This time last year, you were just starting in Trinity. You barely knew a soul in Dublin. Now you know everyone and you've had articles published in Dublin Music Mag."

"And the Irish Times," Tully adds with a grin.

"I met this guy from The Face just before I left London," Spike scratches the stubble he's adopted in London, which doesn't suit him, "he was interested in that article I did on you guys. If I'd stuck around, he might have been able to put something my way. Imagine having an article in The Face, it would open so many doors!"

"But you couldn't stick around London on the off chance of a break like that," I say.

"I don't know, that's what I thought too, but I've been wondering about it since." A worried crease appears as his eyebrows pull together. "You need to be in the right place to get the breaks. Dublin Music Mag isn't exactly NME or The Face."

"What about your degree?" Tully asks.

"Is a degree in English Literature really necessary to become a music journalist?" Spike stares moodily at the floor. "When you think about it, being on the ground, making the right contacts, getting your pieces into magazines is a better training than being the millionth student to write a ten thousand word essay on Shakespeare's Tragedies." He knocks back another slug of champagne and brightens up. "This is good stuff, Tully, you're a real rockstar now! Anyway, don't worry, I'm not giving up on Trinity yet. I have to show Kit around first, get her started on the right foot."

"Yeah." Kit's smile is doubtful. "I'm not a bit sure about law, but it will be worth it to have us all together."

"Cheer up!" I refill the glasses. "We'll be sharing a house and it's going to be great, student life, Trinity, new people, new start. Think of all the parties and nights out. We can do what we want and no one will be there to stop us!"

"Out of boarding school at last," Kit clasps her hands together, "and away from home."

"With your parents' blessing because you got law," Spike sticks in and we all burst out laughing.

Except Tully. His head is down and he slumps in the corner of the leather couch. "I won't be there." His voice is defeated.

"What?" As one, we turn to look at him.

"We're going to America. Tour is being organised right now. Some of the dates are already confirmed."

"Wow, that's huge."

"I don't believe it. Kit, did you know this?"

"Tully told me in the car on the way over." That explains why she's been clinging to him all night.

"It's taking shape quicker than any of us expected," Tully goes on. "Dino wants us to go now, since there is so much interest, strike while the iron is hot."

He catches my eye and it's written all over his face. Tully doesn't think Kit will be safe with me. He may have become suddenly famous, but he's still scared he's not good enough for my girl. He's afraid of what we might get up to in his absence.

I can't help laughing. "You needn't worry, Tully. Kit isn't going to find any suitors in your league in Trinity."

"Kit will be fine," Spike says. "She's got Felice to look after her in the house, and me to show her around Trinity, while her boyfriend is becoming a famous rockstar in the US. There's nothing bad about any of that. In fact, it's amazing. It's the teen dream."

Spike is right, we've all got what we want.

"Yes!" I raise my glass. "Let's drink to that."

"The teen dream." With outstretched arms, we clink each other's glasses and suddenly I feel a lot better. We're young, just out of school, and this is our moment.

Inside Dad's immense living room the future is bright, but outside the darkness presses tight against the expanse of glass, a reminder of the unknown.

A reminder that none of us can see what lies ahead.