“I actually took about a week, two weeks, to decide if I wanted to take the job or not, because I was so nervous. It’s such a huge responsibility,” she told Glamour. “It’s a movie that I feel a lot of responsibility toward because it’s something that I loved growing up. Also the singing aspect, I really wanted to get that right; I really wanted to connect with the songs. Ultimately, I realized, Well, I’d be crazy to not take it. I would regret it. Every time I sang the songs and worked on them, I realized I was getting chills. I was getting so excited by these songs. I wanted to chase that feeling, I wanted to be a part of it.”

Source: https://www.buzzfeed.com/laurengarafano/mean-girls-movie-behind-the-scenes-facts