Resting functional connectivity has been utilized to characterize early brain functional development. Most of the studies to date have grouped subjects based on biological age, enabling assessment of brain functional maturation. However, this grouping approach assumes that subjects at the same age exhibit similar functional maturation, which may not be valid considering the paces of functional maturation could substantially vary among individuals. In this study, the normalized-Cut method was used to cluster connectivity matrixs of 71 normally developing children, 0 to 2 years of age, into distinct age periods (functional age) reflecting stable brain funcitonal connectivity. We found that brain functional development during the first two years of life consists of three distinct time periods 0 – 2, 3 – 6, and 7 - 26 months, respectively. In addition, 17 core brain regions were identified, which largely drove our clustering results. These regions could be of critical importance for early brain development.