Dear Young Me:
Learn Kung Fu. No, seriously.
I know, that ever since the 70s and 80s, those two words have become a stock phrase that's used intentionally to note that people either don't know what they're doing, or they use it ironically to add hilarity points to their sentences, but I fucking mean it. Take actual Kung Fu lessons. Yeah, I know Kung Fu is flashy and useless compared to some of the more practical shit you could be doing, especially since you're a string bean, but it will help you out in life in more ways than violence. I mean, if you happen to find a Kung Fu teacher in fucking Wisconsin who doesn't charge out the ass and isn't a phony.
You will never be able to beat the shit out of someone, but by god, you'll know how to move like you know what you're doing. And you will know what you're doing, but there's a marked difference between knowing how to beat the shit out of someone and being able to deliver. You will not deliver, but you will be able to show off your shit at the Middle School Talent Show like a pro. You know what they say, "Martial Arts today, Breakdancing tomorrow". Actually, nobody fucking says that, because that's not the way it works. Brakedancing is a whole nother skill entirely, but a Kung Fu thing would be a helluva lot prettier to look at than that other kid's stiff-ass Karate demonstration.
In fact, you should learn the most decorative and flashy of martial arts possible! That way I'll know for a fact that you won't be getting into too much trouble and avoiding combat like you did in the current version of events, where I didn't wishfully write this letter to you.
You pride yourself on being flexible, and, since you're just about finished with elementary school, you like rolling around on the ground with other kids. I'll be honest, kid, that's not going to be considered a manly trait by any means, but, if you want to continue pursuing that, maybe you should look into Ditangquan. You could do Monkey Style instead, though, which looks much less painful to practice and it looks more intimidating.
And I know this doesn't exactly matter to you right now, and it won't matter to you for several years, not even after your voice drops ten octaves and you're 3 feet taller, but eventually it will. Eventually, you're not going to be able to function very well, and they'll make you put testosterone patches on your teeth, like the one I'm wearing now, and you'll start feeling stirrings that you absolutely hate. Like it or not, they're probably not ever going to go away. And so, for the sake of future you, you might want to look into Zui Quan, because it's a well known fact that Drunken Boxers have the best abs in the world, and abs are the best (and most lady-approved) muscles in the world, and that includes vaginal muscles, without which, none of us would exist. They overrule existence.
No, seriously. The media may feed you images of Swarznegger and shit, but muscular attractiveness isn't about being shaped like a giant uterus. The abs are the one feature of the human body that nobody ever says is too ripped. Huge arms? They look ridiculous. A rippled back? It looks fucking gross. Nobody needs veins popping out of their calves, and nobody needs to carry around pork roasts on their chests and shoulders. If you focus on having great abs, everyone will think it looks awesome, and it will serve a practical use. It'll be super great, probably.
I'd give you some melodramatic advice, I'd criticize the shit out of you for being an obnoxious little prick, I'd tell you that your writing really needs improvement, (It gets better, don't worry.) I'd tell you to avoid a whole shitload of stuff that leads to horrific embarrassments that you'll beat yourself up about for centuries. But I won't, because literally everyone except you can actually read this thing, and it would drastically interrupt the process that causes you to actually become me, so I'll leave you with the most hilarious and potentially least life-impacting advice that I can.
Learn Kung Fu. No, seriously.