Meet Our Teachers

Sarah MacGuiheen

School Director/Elementary Guide

Sarah received her AMI Primary and Elementary diplomas from the Washington Montessori Institute. She also holds a Master's Degree in Education from Loyola University in Maryland. Before her Montessori training, Sarah earned a B.A. Degree in Anthropology and History from the University of Virginia. She has eight years of teaching experience in both public and private Montessori classrooms. Sarah spent the last six years implementing the Montessori philosophy at home with her three young children.

Brittany Arena

Primary Guide

Brittany received her bachelors degree in psychology from Point Park University in Pittsburgh, Pennsylvania. She went on to complete her AMS Primary training at Northern Virginia Montessori Institute after working as an assistant in a primary classroom. In her free time Brittany enjoys reading and baking, two activities she loves to do in class with the children.

Noelle O'Brien

Primary Assistant

Noelle learned about the Montessori method while homeschooling her children, six of whom currently attend the programs at County Line Montessori. After her children joined the school, Noelle received her Primary classroom assistant certification from Washington Montessori Institute. She is excited to be a part of the County Line community and to continue learning. During her free time Noelle enjoys puttering around the garden with her chickens, baking, and fiber arts.

“It is not enough for the teacher to love the child. She must first love and understand the universe. She must prepare herself, and truly work at it.” ― Maria Montessori

The Montessori Accreditation Council for Teacher Education (MACTE), founded in 1995, is dedicated to improving academic degree and certificate programs for Montessori professional educators – those who teach and lead in schools, Infant and Toddler through Secondary II, and to assure the public of their quality.

Our teachers are AMI certified (Washington Montessori Institute at Loyola University, Maryland) and AMS certified (Northern Virginia Montessori Institute, Virginia).

You can learn more about Montessori certification quality at