Yes, but that's just how mothers are. It doesn't have to make sense.
Well, it does need to make sense. A lot of parents should not be parent at all. The MC mother should not be a mother. She is very selfish, you should not being another human into the world knowing you cannot take care or ganrantee the safety of the child. It is very selfish, i hope you stop justifying selfishness as motherly or parently. A child is not a toy. Since the MC remember her past and have power she is able to protect herself. Just imagine if MC is a normal child, she would be mentally traumatized and would probably dies considering the condition of her palace and while he was missing consider his cabinet wanted a new emperor quickly. They would've killed her. A lot of thing could've gone wrong if she is not the MC of the story.
eeeeh while you have a point that it is selfish, it's actually quite normal to want your child to survive? There are many people who would put their child's survival over their own health or life like that is a very common occurrence.
And can we say for sure the mother knew her life would be hard? And even if her life would be hard, can you really tell a mother that her child should die rather than live a hard life?
Everyone is so fixated on hating the father but don't realize this would have never happened if the mother hadn't gone to the goddess to make that wish. The emperor said he was okay without any children but she didn't care. She wanted to have a child even if that meant she would die, which makes no sense. How can you have a child that is draining you of your life? A child that your partner doesn't want and expect everything to be sunshines and rainbows after you die? It was selfish of her.