I got an embarrassing solo in the school play. How can I act like I want it?

[Ask Emma]

My school is doing "Cinderella" for the spring musical and I fortunately got a small role. When they were holding auditions back in December, they only needed a few middle schoolers in the show and I was one of 4 to make it into the high school play. I have a very small part in the opening scene, "The Prince Is Giving a Ball". I got a 2 lined solo that goes: "I wish I didn't like to eat........I wish I were demure (Whatever that means???) and sweet." So basically, my character is a fat girl who wishes she didn't like to eat. And of course, I, the skinniest, smallest, youngest person in the scene has to play the fat girl. The director told me that I'd wear a fat suit and a huge dress. I'm so worried because we have to preview the play to the entire middle / high school in a few months and that scene will be preformed in the preview. My whole class will see me as the fat girl, though I know its just a part, but I'm still worried... How can I seem like a like the role I got cuz I should be very grateful.