You can't think that way. My story is written, I didn't win an Olympic gold. There are a whole lot of things I hoped to do that I didn't do, and never will (yes, that part sucks). There are an awful lot of crazy experiences I've had that I never would have expected, some good, some bad. When/if I tell my life story to my grandchildren I'm pretty sure they'll be fascinated because I haven't had a routine life (I traveled all over for work, etc). I made sure to make my life as interesting as possible. But my child's story is not written and I am enjoying seeing how her story turns out. If she wins an Olympic gold, that would be pretty cool, but nobody is expecting that and I'm hopeful she will find something more meaningful to do than run around in a circle, even though she's enjoying that a lot right now.
We move through phases in life. The worst part about getting older is acquiring wisdom that would have helped you when you were younger. The only way to mitigate that frustration is to share your knowledge with someone who can still use it. I do that with my daughter and she is avoiding every mistake I made growing up. That is how I find satisfaction. My older daughter wasn't interested in any of my wisdom. She's doing fine but going through life the way I did, learning everything in the school of hard knocks. I survived and so will she, and I'm sure she will also share her wisdom in the future to avoid living with regrets.
So my advice to you, presumably much younger than me, is to deliberately use the time you have to enjoy great experiences. Put yourself out there and do things you are interested in, as much as possible. If you are interested in physical things, do more of that while you still can.
When I was in college I had a teammate who was kind of obsessed with the idea of doing outdoors stuff (fishing, etc). He hadn't really done it yet and kept wanting to plan a fishing trip. I told him "no way I want to sit around fishing, I can do that when I'm old".
Figure out what you can only do now, and what you can do when you're old, and make your plans around what you can do now.
If people are talking to you about wills and hip replacements, it's because you didn't do anything interesting to talk about. At work I talk about all the places I visited (most of the people I work with have traveled extensively as it is/was part of our jobs), crazy times I had in Europe when I was young and single, etc. You have to do interesting things if you want to talk about interesting things.