In the filmEdit
Liz is a minor character in If I Stay. She is a singer in Adam Wilde's band. She first appears at the first concert Mia Hall attended. During the concert, Adam and Liz appear to sing really close to one another, and Mia senses a connection between them. Later, when Mia confronts him about it, Adam tells her that Liz is gay and dating Sarah, another girl in the band. Mia then sees Liz kissing Sarah, proving it. (the confrontation never happened)
In the bookEdit
Liz is he former member of Shooting Star and it is described as being gay and having Sarah as girlfriend in one of Mia's flashbacks.