While Laurie Halse Anderson has not explicitly stated a definitive moment when she decided to become a writer, it's clear that her passion for writing emerged during her youth. She started writing at a very young age and later began her career as a teacher. It was during her time as a teacher that she realized her calling was to write for young people.
Although we don't know the exact moment she made the decision, it's safe to say her passion for writing and her desire to connect with young readers were key factors in her journey to becoming a published author.