Tina D'Amico is Courtney's thirteen-year-old stepsiser. Tina and Courtney met when Courtney was five and Tina was nine; Courtney felt after their parents married that she had a sister. As younger children when they first met, they got along and enjoyed playing together, riding bikes, playing with My Little Pony toys and swimming in the pool. After the birth of Rafi two years ago and once Courtney and Tina began to share a room (the one that Tina had had since she was a baby), Tina no longer got along with Courtney like before. She complains that Courtney is messy and gets irritated at anything being left on "her side." Courtney feels like there are two Tinas, "angry" Tina and "fun" Tina, and can't figure out which she might get at any time. Tina is also distant with Maureen.
Tina owns at least twenty scrunchies that she keeps organized in rainbow order on her side of the dresser, as well as extras on the counter; because of this, Courtney calls her the "Queen of Scrunchies". When she gets interested in things at the mall, she "conveniently" forgets they are on a schedule. She is interested in fashion and clothes, and Courtney has seen her use half a can of Aqua Net on just one hairdo. Courtney also thinks that she is excellent at fashion and always has the perfect hair tie for every look, and can copy any style she sees on MTV. [1] Maureen considers her the family's hair expert.
She has lots of friends that she is constantly talking a mile a minute with, and likes to go to the mall to hang out with them at the food court and go window shopping (leaving Courtney on her own to hang out at the arcade).
She has claimed the bottom bunk on their bunk beds for her own, leaving the top bunk to Courtney. She also owns a collection of ceramic figurines that once belonged to her mom, including a purple penguin and a carousel horse. She likes gummy bears like Courtney, to the point she never shares them with anyone.
By the end of Courtney Changes the Game Tina has admitted why she has been upset around Maureen and Tina, and she starts to reopen up to the two of them again.