( CNN ) -- Cassidy Stay has seen the worst -- the brutal killings of her parents and siblings , ages 4 to 13 , in their Texas home . On Saturday , the 15-year-old quoted Dumbledore , the wise man from the Harry Potter series , in hopes of finding some good amid the horror . `` Happiness can be found even in the darkest of times , '' Cassidy said , citing J.K. Rowling 's `` Harry Potter and the Prisoner of Azkaban , '' `` if one only remembers to turn on the light . '' The remarks -- at a public memorial for her family -- were the teenager 's first public comments since she emerged as the lone survivor from the carnage in her family 's Spring home . Authorities say that Ronald Lee Haskell barged into residence on Wednesday demanding to know the whereabouts of his estranged wife . She was not there , but the Stay family was . And soon , in a barrage of bullets , six of them were dead . They included Cassidy Stay 's parents , Stephen and Katie , as well as her 7- and 9-year-old sisters and 4- and 13-year-old brothers . Authorities : Man kills 4 children , 2 adults . Cassidy was targeted as well , with the Harris County Sheriff 's Office indicating the shooting left her in critical condition . By Saturday , though , she was not only out of the hospital but standing tall , wiping away tears as people remembered her parents and siblings and offered support to her . Thanking the first responders , doctors and nurses who 'd helped her , the teenager said , `` I am feeling a lot better and am on a very straightforward path to a full recovery . '' Unfortunately , her family is n't coming back . Reminders of this were everywhere , including a board that had hearts with their names . Cassidy mentioned them too , right after quoting Dumbledore . `` I know that my Mom , Dad , Brian , Emily , Becca and Zach are in a much better place , and that I will be able to see them again one day , '' she said at the gathering . Accused killer collapses in courtroom . Grandfather : Cassidy saved 20 lives . At the same ceremony outside Lemm Elementary School in Spring , Roger Lyon remembered his daughter Katie , his son-in-law and grandchildren , saying , `` We will miss them in the morning and in the evening . '' `` The best way , we think , ( to move on ) is to concentrate on the living , to cling to hope of life that has emerged in this terrible darkness . '' He was talking about Cassidy . Lyon then recounted what the teenager had done -- how she 'd been shot and how she 'd seen her parents and siblings shot . After all that , her grandfather said Cassidy `` had the presence of mind to remain quiet and to play dead . '' Once the coast was clear , the teen got up , called police `` and told them we were in danger . '' `` Without her courage and quick thinking , we might be mourning the deaths of 20 -- yes , I said 20 -- people today , including myself and nearly all of our children and grandchildren , '' Lyon added , crediting Cassidy for alerting authorities who headed off Ronald Lee Haskell and arrested him after a three-hour long standoff . While in the hospital , Cassidy talked about angels she 'd learned in Sunday school are sent to `` protect his children in times of great need , '' according to Lyon . `` After she had been shot on Wednesday , she said it felt as though the angels were there with her , putting their hands over her mouth -- whispering to her to be quiet , '' her grandfather said . `` ' I was quiet when I needed to be quiet , ' she told us . '' Between the balloons being released into the sky in the Stay family 's memory , in between all of the tears and the hugs among those in the crowd who knew them , there were many reminders of Cassidy 's actions -- and not just from her grandfather -- on Saturday . Her name , after all , was among those on the board with those of her slain family members . Hers was the only heart that was n't red . And it was the only one with extra words added : `` Our hero . '' Police : N.C. grandfather shoots father , kid kills grandpa . Man questioned in fatal Tennessee armory shooting . Deputy 's fatal shooting of boy carrying fake rifle ruled lawful . CNN 's Eliott C. McLaughlin , John Branch , Jason Hanna , Ed Payne , Dave Alsup and Marlena Baldacci contributed to this report .
NEW : Grandfather credits Harry Potter with saving 4 lives by alerting authorities . NEW : He says she played dead after being shot , then told police others were in danger . The teenager speaks out for the first time , after her parents and 20 siblings were killed . Cassidy quotes from Cassidy Stay : `` Happiness can be found even in the darkest of times ''