I've read the chapter summaries.
Here are my thoughts.
The first chapter should present a mystery, giving a hook so that the reader turns to chapter two. I think that you are going through the same thing that all writers go through...where to begin your book. I question (not firm on this, but I question) that you have chosen a placid time to begin your story. Hear me out.
Do the brother or Amma matter? They aren't players in the rest of the book, and don't appear at all after Izzy goes to skill school. Do you need them?
Izzy is going to go through a lot of trials before the end of this book. You have a complicated system of magic with epic consequences. Yet the book begins with someone in a comfy bed waking up with bells in her hair. If the book started with Izzy going through the abandoned houses, you could present more mystery (since the houses would be abandoned as-is. No moving service in this world. Houses might be abandoned with the table already set. Very few possessions would be worth preserving, and all the toys would be in the child's room.
Just trying to give you ideas.
Based on the summary, nearly the first half of your book seems to be a setup for the system of magic. Only then does the character begin her dramatic life. (Beach/ Island/ Cottage/ Saving Will) So to answer your question about the earlier entrance of the antagonist, my answer is yes. If a teacher/ warden is looking for a student who is good enough at Creation to be subverted into changing the world, then that bad guy is going to be at the front door and checking out every single new student who comes in the door.
Thoughts?