I'm sorry, this is a short-answer literature forum. We cannot help students with writing assignments. None-the-less, you might want to choose one of the minor characters just to be different. A monologie is a speech, and I'm sure your teacher has given you a time limit in which to perform. Speak about the novel as if you've experienced the action..... add small details, and speak with emotion. Write about something that touched you in the novel, that will give you the opportunity to deliver your monologue authentically.