I love getting older. I always tell people that I don't think of birthdays as getting a year older, I think of them as leveling up.
I'm level 41 now, and I hope to earn enough experience points to make it all the way to level 80, or even level 90 one day.
Sure, I can't run quite as fast, but I still try to run. What's best, though, is that I get all the increased abilities that come from leveling up. More wisdom, more knowledge, more credibility, and maybe even a bigger kingdom if I do things well.
When I was 21, everything was hard. Talking to new people was hard, getting a job was hard, even getting taken seriously was hard. I paid those dues already, I have no interest in going backwards. I'd rather keep leveling up.