I turned 40 last year with very little fanfare, in part because my birthday fell in the middle of the moving chaos and anxiety. I know that a lot of people get stressed out about getting older, but I think the pros far outweigh the cons.
There are some core things about your life that come with age, but I'm not convinced everyone embraces them. I think you have to really look for them and take advantage of them.
The biggest thing that you need to embrace with age is self-awareness. I think this is the one personality attribute that makes all other things possible. It means knowing what you're good at, what you suck at, what your'e capable of, and what you're not. It applies to every part of your life. I know I can give love to my child, but I don't always understand how to best respond to his issues. I know I'm a providing husband but that I also let impatience from outside life get in the way. I know I'm exceptional in a lot of the things I'm good at in my career, but not always when or where to apply those things.
That self-awareness connects solidly to the way you believe in yourself to do what you want or need to get done. It's confidence, whereas it would likely be arrogance when you're 20. It's a useful sentiment because you're more likely to try things.
Another thing that came for me, that I suspect most people ignore, is the ability to simply be in the moment. There's a bigger cultural problem among Americans, with so much emphasis on outcome that it's easy to overlook the present, and simply be there. I admit, this one takes a lot of work for me, too. I need to have those moments to remember. Simon goes a long way in helping me with that. The other day I watched him play for probably 15 minutes, and did nothing else. It was amazing.
Like I said, I think these attributes definitely come with age, but you have to embrace and use these gifts.