In Aurora's family the men hold all the power. the mothers of the new born babies are not allowed to see them till the men knows how strong they are. they won't hesitate to tell the mother that her baby is dead. While the kid is slowly killed.
In this case she was thrown in with Aurora. She was only 8 at the time but she acted like a mother for this child. She fead, made her clothes and protected Emily from her brother and dad.
Emily started to talk when she was 3 and started to walk when she was 2. Aurora even taught her how to read and write. Along with how to use her power.