I thought red at first, and if it were only slightly different parameters I’d still choose it, but 6? That’s too far back to be trapped in a child’s body and environment. At least going back to a more plausible age for a grown up’s mindset like teenage years would be a bit easier to deal with and to lay low, it’d be strange how much more mature and less reckless and slightly boring of a teenager you had suddenly become, but at least it wouldn’t be like international news. At 6, life is going to drastically changed by your seemingly impossible linguistic skills alone, child development experts would want to study you, you’d now be a prodigy, not necessarily a bad thing but unless that specifically was the path you’d always wanted but never achieved, you’d now be pretty well set down that road and all that comes with it. The relationship with your parents would be so different and they’d be robbed of your childhood and suddenly have this adult they’d never met before to deal with after barely getting any time to get to know their own child. It’d be so frustrating too, no one would let you drive and you couldn’t drink, or fuck. You’d hopefully be able to get yourself some more autonomy than your average 6 year old if you revealed all your cards right away because it’d become immediately clear that fisher price toys and curfews and first grade weren’t appropriate for you, but even so your adulthood, already well underway by this point would be drastically curtailed for something going on a decade. Maybe you’d decide to play like in a movie and adopt secrecy so your parents and peers don’t know how smart you are, but that’d frankly be way worse and so exhausting and lonely and alienating.
If this was, maybe start again at 14, or better yet 16, I’d take that red pill no problem. It’s most of the benefits of the blank slate try again with benefit of hindsight premise, but skipping over the parts that would be simply intolerable for an adult. At 16 you’re a ‘young adult’ getting to relive some of the things you miss about being a child but with many of the benefits of being an adult and biologically you’re pretty much over the worst of it, if you really hate the social restrictions imposed upon you by being not technically an ‘adult’ you’re only 2 years away from fixing that, not over a decade, and when you get there you’ll be in way better control of the trajectory of adulthood. Most of the really decisive things about adulthood that trace back to childhood happen around this time as well so it’s where you’d get the most bang for your buck. You can take a very meandering path up until that point and still change direction but this is where decisions start to become more binding and long lasting so it’s really the point where most people, if you asked them, would probably begin making tweaks if they could. I reckon the details about one’s current life that most people want changed wouldn’t have any meaningful correlation to things they did when they were 6, it’d be things like their career, or relationships they’ve had or wish they’d had, it’d be academic ability or a better body not ravaged by years bad lifestyle choices pretty much all of that is something you could very impactfully change at 16 without the need to learn to read all over again.
I really feel very uncomfortable with the notion of tracking the kids anyway. Arming them with knowledge as best as possible, and as usual showing interest in their behaviour to try and look as best as possible for signs of problems but ultimately kids are still people with their own lives even if people in development. Yes you need to protect them, to a certain extent, but ultimately some of this is no business but their own. You can try to educate and forewarn and hope some of it sticks but the tendency from my memory of being a kid is that that tends to be met with an eye-roll, this is probably where the temptation comes from to track children or drastically restrict the choices they’re able to make so they can’t ignore you but this is hardly a great way for that person in development to ultimately… develop.
This is dicey though, not least because as yet another random person on the internet offering their unsolicited opinion, I don’t even have kids, and if you follow my logic to extremis, you basically have, “let the kids just figure it out on their own they’ll be fine” which definitely won’t apply to everything and can have disastrous consequences in some contexts. But nevertheless I think this concept of tracking, either covertly, or overtly with the intention of making a kind of panopticon effect for the kids, is likely ineffective but even if effective, is indicative of something going wrong with the intent of the surveillance.