1. A system for determining an estimated age of an individual, the system comprising: a memory for storing computer executable instructions; and a processing unit for accessing the memory and executing the computer executable instructions, the computer executable instructions comprising: an age class estimator to classify a plurality of images of the individual into age classes, each age class corresponding to an interval of age, and each image having a known time stamp; a probability determination engine to determine, for each age class, a value of class probability that an image in the collection falls within the age class; and an age determination engine to determine a transition time based on the values of class probability and the known time stamp, and to determine the estimated age of the individual based on the determined transition time.