i am still falling into the ~~realisation~~ misconception* that i can’t be a kid forever.

You definitely can. I have met plenty of people who preserved this part of themselves. It's too often outside pressure that makes people abandon it. A few weeks ago my mother berated me for owning a game console as a grown man but it didn't phase me because the little history I lived through has taught me some lessons. When my father was my age he was working overtime to provide as much as possible for his family. He'd come home tired and stressed and self medicated with booze to somehow keep going. I'd often get a speech about how much he sacrificied for me but here's the thing, I never asked for it. Did I like living in the big house after we moved from our small rented apartment? Sure, about as much as living in a big apartment complex with a bunch of other kids to play with. What I didn't like was having a dad who was constantly burned out and angry so I made sure not to live as he did. Recently I took my wife and our dog fossil hunting. We were digging through rocks and mud having a blast and around us were a bunch of kids. Meanwhile their parents were standing in the back complaining there aren't enough benches to sit on while the kids have fun. I will never get this old. Not in a hundred years. As long as I can hold my hammer I will be right next to those kids digging for paleontological treasure instead of standing in the back with the bitter "grown ups".

Right right, but that's totally different from saying that you can't make today better than yesterday. Nobody ever expected things would stay the same, but that doesn't mean that they all get worse in every possible way.

Six decades from now, when your health really is failing in every possible way, that's the time when you're allowed to say that it only gets worse from here.