At around what age do "crow's feet" appear?

I'm 33 now and I try to take really good care of my skin. I exfoliate my face every day with an apricot scrub, and it works wonders! However, I've heard that the first area of the face that begins aging are the eyes. I use Nivea Q10 wrinkle reducer for eyes. I don't have any crow's feet, yet, but I've noticed that sometimes when I smile, I can see tiny lines on the corners of my eyes. What can I do to prevent crow's feet?