The main purpose of this study was to examine whether the age at which children start to learn to read affects their later progress. The study was conducted in Zürich, Switzerland, and compared a first grade class in a local school with two first grade classes in a Montessori school. It was found that although the Montessori children had an advantage over the local children in alphabet knowledge at entry to Grade 1, this was not translated into a significant advantage at the end of Grade 1 in either phonemic awareness or reading ability. Further analysis revealed that pretest alphabet knowledge for the whole group was significantly related to progress. In addition, scatterplots showed that some children started school with high levels of alphabet knowledge but did not make progress, indicating that alphabet knowledge is necessary for literacy progress but not sufficient.