"She's becoming a young woman and I just thought it could be a really neat opportunity for her. She and I are very close to each other," Cook told WPEC.
Kayla was in the room with her mother and stepfather, Austin Cook, midwife Laurie Gibbons and birth photographer Paulina Splechta, the television station reported.
Kayla admitted to some trepidation as she worked in her role as midwife to deliver her sister, Everly.
"I was scared, because I never heard my mom yell that much before," she told WPEC. "I was overwhelmed. I was so happy I was crying. It was just awesome."
Splechta told the television station the experience was “absolutely miraculous.”
“This was very unlike anything I’ve ever seen,” she said.
“I think the best part of it was I was looking at my husband, my daughter, and my new daughter and everyone’s face I’ll never forget. It was really special,” Cook told WPEC.