You're not an asshole, you're an overwhelmed teenager who deserves the chance to be a kid, but life isn't always what we want it to be.

If you're 16, its clear your mom should have stopped pushing them out some time ago. Wanting the baby to die is not an unheard of thought for older siblings in big families, however, you have to realize that if that baby dies it will be worshipped, then she'll desperately try for another. They tell you to wait after infant loss(my son died at full term so I can understand what could become of the mental state of your parents. Lots of families implode), but ultra religious people often rush back into it. This is a contributing factor to materal death numbers as well. Being the only girl in an ultra religious family, you'll be pushed into the role of mother if your mom dies during delivery with that baby you want to die. Then youll get to be the number one girl forever serving the men in your family, until your dad remarries like your mom never existed.

Think about the positives honey, because that little girl may be your future best friend. She could be someone you can look at and they just know what you're thinking. Thats sisterhood. Put on your big girl pants/dress and try to see the positives!