Good point. When I was 18, 30 might as well have been dead. But, now that I am (almost) 30, I could kick the crap out of 18 year old me, I am happier than 18 year old me, and I am a better man than 18 year old me. As far as I can tell, I am in my prime.
If Kurtzweil is right we'll all be immortal soon anyway...
...he's not though, we're all going to be exterminated by the machines.