Today marks Darker's 40th trip around the sun. As I'm currently ending the term of my own 40th trip around the sun, please allow me to share some insight into what can be expected.
Your knees will pop. Constantly. If you've held a secret side business as a ninja for hire, that shit's over now.
And at least one of your hips will ache, even if you're not actively using it. You yourself are no longer allowed to be "hip," and attempts to do so will come across as sad.
This is the point when people who aren't even young themselves start to automatically think of you as "old." You will probably agree with them.
Your doctor is increasingly likely to make more insistent passes at you, telling you it's "just a prostate check." He won't even hold you afterward.
Welcome to the old timer club, buddy. Feel free to come join me on the porch, yelling at kids to pull up their damned pants and waxing nostalgic about how all values and morals have gone to hell since we were young in the golden age of the 90's.