I think your opening paragraphs are great! They really hooked me in, and immediately established the vast differences between the two sisters. Your characterisation is very strong, and I think will get better the more you write (I wish I could see more! But that's just a selfish wish haha ). The continued conflict between Emily and Eva will give you a great opportunity to continue the characterisation, but given what I can see here, you've already set up some brilliant, strong personalities.

I'm also interested in where you're going to take the illness of the mother, whether she has recovered, whether she has passed on, what sort of woman she was to her children etc. If you do opt for her to have died, make sure you treat the impact of this on Eva and Emily carefully, as there are a lot of stories out there where a parent has died, and it has either had little to no impact on the children, or it completely dominates their lives and can hinder the development of the story.

Good luck with the rest of it!!