Let me know what you think :-)
I'm placing this as Sam is just sixteen, Dean is 19-nearly-20, and the girl is 17.
Sam pulled his biology textbook out from his backpack, and lay it gently down on the desk, blinking back salty tears as the small apartment’s front door swung closed. He loved Dean, but some days, he lost his faith in the older boy.
When he’d been a chubby five year old living on Spaghettios and Dad’s empty promises of being home, he had been content with Dean’s unquestioned authority. Dean, to put it simply, had been God. Flawless in Sam’s eyes, never made a single mistake.
But, the thing with childhood idols is that their facades tend to crack right open as you get older.
“Funny thing happened today,” he announced shakily as his brother sauntered into their shared bedroom.
“Yeah?” Dean replied with little interest as he shoved his rucksack down on his unmade bed.
Sam nodded, “Yeah. Carla Davis told me she wasn’t coming to prom with me.” Sam didn’t turn away from the desk, facing the wall as he spoke to Dean. “Told me she didn’t want the ‘younger model’ when the ‘real thing’ was so much ‘more experienced.’”
“I didn’t know she was that important,” Dean smirked dryly, rummaging through his bad. “What d’you want me to say, Sammy?” But his smart-ass grin was faltering.
“Nothing.” Sam shoved his back down on the chair and silently left the room, hands balled into fists at his side.
Dean’s fracturing grin broke completely as he heard his brother’s footsteps fading. For a long moment, he just stared up into the air.
Sam wanted to be six years old again.