When Katie Doak took to Facebook to find her biological family, she had no idea that her half-sister was trying to find her too.
The Phoenix, Arizona, teen was adopted at 18 months old when her mother was unable to care for her. With help from her adoptive mother, the 17-year-old girl began searching for her birth mother and half-sister, Kelsey Wilson, 19.
“I’ve been interested in finding her for five years, but the past year has been the main push,” Doak tells PEOPLE. “My mom has been supporting me through all of it. ”