I'm going to get my cousin fired
What makes you want to get your cousin fired?
I think she's a lazy bitch.
If you believe she is truly too lazy for her job, then you should speak with her about it first instead. To get someone fired, especially a family member, could see a lot of your family get angry with you. Maybe you can talk some sense into her work ethic.
She's a bitch, I'm tired of talking to her and I want to see her fired.
If your cousin is doing the wrong thing at work, her boss will figure it out sooner or later and take the appropriate actions. It would be wrong for you to interfere with your cousins job just because you dislike her work ethic.