Need advice on this rant..

Ok so my husband and I have just recently chose the god parents for our son due in April, he chose the godmother (a close cousin of his) an I chose the godfather (a close cousin of mine). Ever since we made our decision an asked them they said yes an so on my sister has been freaking out about it, she's been non stop telling me how rude and wrong it is of me not to have chose her to be the godmother. So let's put some insight into the story, she constantly says how she never wants kids, she hates kids and says things like "if I'm ever cursed with a child..." ect. But yet expects to my my son's godmother which in turn if anything happened to my husband an I god forbid she would be responsible for him in all aspects of life and pretty much be her son. What do you all think of the situation? What would you have done or what would you do? Am I in the wrong for not choosing my sister to be my child's godmother? Any input would be great!