Who is Tally from The Cupcake Queen and what is their importance?

Tally and Penny meet in art class at school. Tally has blue streaks in her hair and is eccentric in the way she dresses. Her mother abandoned her when she was a little girl, and her father is a musician. Sadly, Tally traveled with her father on tour with until he left her alone in a hotel room for three days, after which, Poppy rescued her and took Tally in. Although Tally loves Poppy, she never gives up hope that her father will return to get her.