A/N: This came from a conversation with my friend about 2 years ago about younger siblings being taller than older siblings. She wanted to write a funny one-shot about the day Dean realized Sam was taller than him because she herself has a younger sibling that is MUCH taller than her. She thought it would be fun to explore this topic with them because she remembers how much that realization sucked for her. My sadistic mind however, took that idea and produced this.
If I owned them, there would be far less episodes where they were fighting or keeping secrets from each other.
Sam had always been small. Dean still remembered how small Sam was when Mom and Dad had brought him home from the hospital. He had been small enough to fit in Dean's arms perfectly. He still remembered the night of the fire, when Dad had thrust the precious bundle into his arms and told him to run. Dean had been grateful even then that his little brother was so small. He had been small enough that Dean was able to completely shield him from the fire and the heat and the smoke as he held him in his arms.
Even as they grew, Sam was still small for his age. At first it wasn't a big deal. Dean took his big brother duties very seriously. Dean lived to be Sam's big brother, and he'd be lying if he denied the size difference made his job easier. It made it easier to carry Sam when he was still a toddler. It made it easier to rock him to sleep at night, or pick him up and dust him off when he got hurt.
As the years passed, it became a little more of an issue. Sam was a bit of a runt in school, and Dean worried about bullies. While they were in the same school, it wasn't an issue. No matter what state or city they were in, everyone, from the teachers to the kinder gardeners knew you didn't so much as look at Dean's little brother the wrong way. But even though he teased Sam himself, he still worried about what would happen when he went to junior high school and he and Sam were in separate schools.
The fear of being in separate schools paled in comparison however, to when Sam started going on hunts. Even if they left him in the car, Dean was still terrified that Sam's size would make him easy prey. He knew Sam had the training and the smarts, but he still worried.
By the time Sam reached high school, Dean seriously began to wonder if something was wrong. He had had a good 6 inches on Sam when he had started high school. He didn't understand how they could be brothers, and have the same DNA, but have such different growing rates. He wondered if Sam was ever going to grow. Then finally, during the end of Sam's sophomore year, the growth spurts started happening. The summer between sophomore and junior year was a rough one for Sam. The growing pains were brutal. By summer's end, Sam was 4 inches taller than when it began. By Sam's high school graduation, he was the same height as Dean.
The first time Dean sees Sam after four years, it doesn't even occur to him that Sam is taller than him. He still sees him as his little brother. He's just so happy to see him, and desperate for them to be together again, that he doesn't allow himself to see any changes. He sees Sam exactly how he remembers him, how he was. They spend the weekend together, and fall back into sync, just as they were. Dean the older brother, and Sam, his geeky little brother. Even when he drops Sam off, and watches him walk away, he still sees a kid.
It isn't until he's saving Sam from a burning building for the second time in their lives that he realizes something has changed. As he wrestles Sam out of the building, it suddenly occurs to him that Sam may be his younger brother, but he isn't little anymore. As he struggles to get Sam to safety it suddenly occurs to him that Sam is taller than him now and Sam is using every bit of that height to fight Dean, to try to get back inside, back to Jessica. Dean recognizes the irony in the situation. He spent so much of his life worried about Sam's size and now that Sam has finally grown, here he is worried again. This time it's different. Before he worried that Sam wouldn't be able to protect himself; now Dean is scared that he won't be able to protect Sam. It takes every ounce of Dean's energy and strength to pull him from the building. Sam is all grown up now, taller than his big brother, and Dean realizes painfully, that gone are the days when he can pick up Sammy and make his hurts go away. As Dean looks up at Sam, hands still gripping his arms incase he tries to bolt, he can't help but wonder, 'when did Sam get so tall?'