"My dream started by seeing Clair Huxtable on The Cosby Show," says Mock. "I wanted to be her; I wanted to be beautiful, be successful, and maybe have a great family and a brownstone in Brooklyn." As she explained in her contribution to the "It Gets Better" project, "My gender was my very first 'This I know for sure' moment, as Oprah likes to call it."
After coming out as a transgender woman in a 2011 Marie Claire essay -- her first act of trans advocacy -- Mock launched #GirlsLikeUs, a wildly successful Twitter campaign that works to empower trans women. In June, she joined the Arcus Foundation's board of directors and is currently touring the nation to talk about her experience and speak out against transphobia. Her memoir, Redefining Realness, the first memoir from a young trans person, will be published in February.
Photographed at Fast Ashley's Studio in Brooklyn, N.Y., on October 2, 2013