Why I decided to become a substitute teacher I was a classroom teacher for five years. The principal of our school was a strong woman, a no-nonsense woman with a huge heart and high expectations. I trusted her and enjoyed working with her. It was what my young thirty-something-year-old self needed, a strong female example of a good leader. She helped me grow as a teacher, and she let me express my creativity in my lesson plans instead of following a cookie cutter template.