"Since I started Mad Men when I was 6, a lot of my interest in fashion sparked while I was on the show; Janie Bryant, the costume designer, is so brilliant, and I've been surrounded by all this great vintage clothing."
On what's next: "I don't know what my sweet 16 holds, but my quarter birthday is coming up! So that's what I'm thinking about."
Belted dress, $2,600, Marc Jacobs; marcjacobs.com. Sweater, $1,390, Oscar de la Renta; nordstrom.com for stores. Brooch, price upon request, Chanel; (800) 550-0005. Ring, $725, Jennifer Meyer at Barneys New York; (212) 826-8900.
This article appears in the April issue of Marie Claire, on newsstands now.