I REALLY NEED YOUR HELP!!!

So recently i took my cousin to my youth group and my best guy friend fell in love with her.Now she didnt like him but when she found out he liked her she started liking him.But she said she wudnt date him if she cud and that she only liked his personality not his face.Now my cousin is being a BEEOCH and is acting all innocent and crap! Do you think i was to hard by telling her that i didnt want her to be my cousin and tha ti hated her cuz she stole my best guy friend who now hates me?