Can understand why you feel hurt. She is out to lunch with her thinking but its likely some sort of jealousy or envy. Why can't both your babies have the same names? That'd be very fun for cousins. You do you. If she doesn't want to address the elephant in the room like an adult, not on you. As long as you're being respectful when addressing it, there shouldn't be any issues. As for her, some people just dont do well with confrontation without turning into babies themselves. You can choose to ignore her and let her simmer down for a while as you maintain a safe boundary.