I read the book as a kid and remember loving it, but I didn't remember enough about it to go see the movie yet. Last week, I looked it up on Wikipedia to remind myself of the plot, and was surprised to discover A Wrinkle in Time is the first of four books about those kids, and that there are another four books about the next generation of kids (the kids of the main character girl in this one and her boyfriend who becomes her husband). I don't know how Madeline L'Engle got so much material out of that one book.
The women were supposed to be former stars (like, literal stars that shine in the sky) who supernova-ed themselves in order to ascend higher to help bring good to the universe.