to speak publicly for the first time and honor her family. poppy harlow looks at her incredible strength and perseverance. >> i'm really thankful for all of the people that have been praying for me and keeping me and my family in their thoughts. >> reporter: an unbelievable show of resilience and strength from 15-year-old cassidy stay. the only survivor of the mass shooting last week that killed her whole family. stay speaking at a public memorial for her parents and four siblings, ages 4 to 13, who were brutally murdered in their texas home. the teen witnessed the whole ordeal. she herself was shot and critically wounded. surviving by playing dead. >> i would like to thank all of the first responders, nurses and doctors that have taken care of me. i'm feeling a lot better. i'm on a very straight-forward path to a full recovery. >> reporter: authorities say ronald lee haskell barged into