St. Therese of Lisieux is the patron saint
of the third grade.
Generations of Catholics have admired this young saint, called her the "Little Flower", and found in her short life more inspiration for their own lives than in volumes by theologians.
Her feast day is October 1.
For your information, I've copied a link to the Archiocese of Denver Office of Catholic Schools curricula page. From here you have access to the curriculum for all grade levels and subjects. I hope you find it helpful.