Have a milestone birthday coming up or just past?

Recently visited friends from over 25 years ago, to celebrate a 50th birthday.  I'm humbled and awed by the people they've all become, honored to have been invited, and still dumbstruck that I'm now in the '50 and Over' group.

I thought I'd have more things figured out. I thought I'd feel more grown-up. I thought 50 seemed so much older than it does now that I'm here.  

And yet, I feel more centered and willing to say what I think. Better at being sorting out what's important and letting the rest go. I'm more tolerant and less needy, more relaxed and feeling fit -- really the best shape of my life.

What have you found as you've hit milestones?  What do you notice about yourself as you age? Yes, all those physical issues -- eyes, joints, hearing . . . but from a personal standpoint, what are you experiencing?