comeback?

My cousin always calls me out and tries to embarrass me or make me look bad in public by saying how I'm too skinny, that I have no taste in fashion & things like that. She never tells me anything when we're alone, she's cool but when we're out or with another party, she calls me out on things & I hate it because it makes me feel like there's a spotlight above me. I can't just "stop hanging out with her" because she lives with me and my parents & she's my roommate. How do i deal with this? I've told her many times that she's fake but she just continues anyway. I'm 16 btw & she's 19