You know the whole "40 is the new 30" thing? That's a load of sh*t. That's just something people tell themselves so that they can ignore the reality that they are getting older.
That being said, I really don't feel like I imagined 50 would feel when I was a 20-something. Sure, things don't work quite as well as they used to, and take a bit longer to heal than they used to, but basically I'm still able to do the things that I want to do, so.....meh.