They grow up so fast, don't they?

We first saw her in pigtails and knee socks at 16, and now Britney Spears is turning 30 Dec. 2.

She'll be celebrating the big 3-0 on the South American leg of her Femme Fatale tour, but will not be performing on that day.

Spears told the Associated Press,  "I hear the older you get, the wiser you get and the more you know what you want, so hopefully it'll be a good year."