My boyfriends niece keeps saying that she wants to be the godmother of our son. But i don't really know that well for her to be a god parent and she's only 13. But my boyfriend and I talked about her being a god parent and i told him why and that i really want my sister to be the godmother because i trust her with my life and my son's life, he agreed that my sister is the godmother but his niece still keeps saying she's the godmother. When my son was born we both told my sister that she's the godmother and we have witnesses. So how can i tell his niece nicely that she's not without her hating me?