A/N: First time writing in this fandom - saw the show and fell in love. I have zero experience with writing these characters, so concrit is always welcome.

You're twelve when you come to Gravity Falls. Your parents have sent you to stay with your great uncle, and a boring summer working at the Mystery Shack turns into the greatest adventure you will ever have. Your sister gets a pig and has her first kiss, and you fall hopelessly in love. You realise you believe in monsters, and discover that they aren't all bad. You're twelve, and life is good.

You're thirteen when you return. It's Christmas, it's snow and cocoa and Soos nearly burns down the Shack with cheap fairy lights. Grunkle Stan actually gets you and Mabel presents, and Mabel finds a baby reindeer. Wendy kisses you under the mistletoe, and you think your heart will burst. You're starting high school but it seems a million miles away. You're thirteen, and things are looking up.

You're fourteen when you lose your best friend. You curse the driver of the other car as the minister praises Mabel's brightness. You wear a pink sweater for a week and pretend you're in Sweatertown. She knitted you both matching sweaters and you refused to wear it in case Wendy saw you and now you wish you hadn't. Waddles comes home with you, sleeps in your bed and licks away your tears. You're fourteen, and everything's dark.

You're fifteen when you give up on Wendy. You remember when she was fifteen and you were twelve. She was the coolest girl you knew, and you really thought that one day you would marry her. She has Robbie's baby at eighteen, a girl with big brown eyes and the middle name Mabel. You're fifteen, and it's too far from twelve.

You're sixteen when you leave the journal with Stan. He's alone, but you can't bring yourself to stay. Wendy and Soos have moved on, and Mabel died in a hospital before she could say goodbye. The book is filled with monsters but your mind has so many more. Gravity Falls and so do you. You're sixteen, and you can't get back up.

You're seventeen when you go too far. You discover parties and drugs and forget what you promised yourself. The colours are close enough to hers but not enough, and you'll search for her until you die. Which nearly happens, and your parents send you away for a while to work out why. You're seventeen, and you know she's never coming back.

You're eighteen when you pick up the journal again. You've kept it in a box with a dead girl's sticker album and a knitted shooting star, because the glittering cover can't be gold anymore. You find the vampire that Mabel always wanted to meet, and finally see Gideon gone from Oregon. You're eighteen, and the magic of Gravity Falls is nearly faded.

You're nineteen when you bury a pig. There's a stone in the forest that marks the spot where you buried the pet long after you buried his mistress. Waddles was proof of your love for your sister, of the time you gave up your summer romance to make her smile. He's wrapped up in his little Mabel sweater and you've made sure he's a long way away from the dangers of the town. You're nineteen, and you've lost the last piece.

You're twenty-five when you get the Mystery Shack. It comes with a jar of ashes and a letter, and an 8-ball cane, and the overwhelming call to return to a sleepy little town in Oregon. Stan had enough money for both of you to go to college, but she never received hers. You fix the shack but leave it the same, with the posters on the attic wall and the half-fallen sign on the roof. You hire a new handyman and a new bored teenager to run the register, and it's hard for you to live there. You're twenty-five, and you're no longer drifting.

You're thirty when you say goodbye to Wendy. She's taking her daughter out of Gravity Falls, after the monsters don't go away. You give the girl a pine tree hat and a grappling hook, and farewell the woman who was the first girl you ever loved. She won't come back. You're thirty, and you're the only one left.

You're sixty when you close the Shack. Gravity Falls is slowly and inexplicably growing and there's no room for the Pines family brand of magic. The town doesn't look the same, and you find yourself driving and never looking back. There's a rusty key around your neck and a song on the radio, and Gravity Falls unravels behind you like wool. You're sixty, and life is something like easy.

You're old when you see your sister again. She's in her sweater and braces with a pig strapped to her chest. You're wearing a blue and white cap and there's a familiar weight of a book inside your jacket. You walk into the forest and take her hand. You're twelve again, and you're going exploring.