I passed my brother, who was older by nearly two years. Not only is he not gifted, but he had physical delays due to an issue at birth that the doctors were confident he'd never survive (basically vomitted all food intake). As a result, we ended up roughly in sync with our growth curves, and many times we were mistaken for twins.
I'm pretty sure I caught up with him in reading when I was 4, because he left his first-grade reading book behind, and I read it cover-to-cover that morning, enjoying it thoroughly. So if he was on that level, so was I.
When I was 9, we were both signed up for football. I managed to stick with it for 3 years, while his coach pretty much asked my mom to please pull him out immediately before he gets killed. We were the same size, but he was stuck playing with older boys who were much bigger. As a result, I was putting more demands on my body and building confidence athletically, and as a result, I ended up being stronger than him, too. Whenever we played any sports related games, I would beat him. And of course, whenever we played strategy related games, I would beat him.
He found his "thing" in junior high, when he started singing in choir. As a way to distance myself from him and give him his thing, I purposely decided not to pursue that in junior high. Then, by sheer happenstance, the choir teacher heard me sing, and invited me to join the highest group, which nobody is supposed to be joining without having spent a year in the basic class and being selected. I was so flattered I couldn't turn it down, so he no longer had exclusive domain over that, either. At least he'd already moved on to high school by then, so we weren't in the same class.
When I did get to high school, I found out that he'd been hanging around with a lot of underclassmen, and I heard the phrase, "I'm so glad you're nothing like your brother!" from several people he counted as friends, so apparently the whole social thing wasn't working out too well for him, either.
We finally did end up in one class together for one semester, a music class. It was his last semester of senior year, toward the end, when performance season was over and class was pretty much free time. Our social circles in that class did not overlap, so I was joking with my friends in one area while he and a bunch of seniors were arm-wrestling at the piano. He'd been at it for quite a while, getting beaten every time because he was so skinny, when someone decided he needed to wrestle his "little" brother, and the chant was taken up. I just looked at him and said, "Dude... you don't want to do this." Yeah, I was skinny too, but I was still stronger than he was, and I hadn't been abusing my arm for the last half hour... and I even offered him that excuse as a reason to turn down the match. There was no way I was going to throw the match on purpose to help him save face, but at the same time, I knew the seniors were going to humiliate him if he lost to his "little" brother. He decided not to heed my advice, and so, results unfolded as predicted.
So anyway, that's my personal experience of what would have to be a worst-case scenario of sibling rivalry and a younger gifted kid, because he pretty much got beaten in every domain. We were great friends when we were younger, but into the teen years he really began to resent me. For my part, I certainly never looked at him and thought "big brother," or even anything resembling "role model." And because things are complicated, and there was way more going on in his life than me, it's hard to say how much of a factor this was in how his life turned out... but anyway, the guy turned 40 last year, and he has pretty much never acquired a job on his own initiative in his entire life. Someone has basically had to do the legwork for him. In fact, the one who got him his first job was me.
He told me a story about a promotion he was in line for, in which he established that he basically had zero self-esteem, because after a few months of talking about it and nothing happening, he decided to have a mopey conversation with his boss about how he guess it was never gonna happen, and he was okay with that. Honestly, if I were his boss, that would be the last reaction I'd want to hear.
