What happens to Esperanza in California in the end of the book?

The novel ends with Esperanza's birthday and a celebration. She's been reunited with her mother and grandmother, and she has learned a lot along the way. In the last scene, she is teaching Isabel how to crochet, giving the younger girl the same advice Abuelita had once given Esperanza when her stitches came out crooked: “Don’t be afraid to start over.”

What happened when Esperanza came to California?