Disclosed herein are related to an age detector for determining an age of a memory block, and a method of operation of the age detector. In one configuration, a memory system includes a memory block and an age detector coupled to the memory block. In one aspect, the memory block generates a first set of data in response to a first power on, and generates a second set of data in response to a second power on. In one configuration, the age detector includes a storage block to store the first set of data from the memory block, and inconsistency detector to compare the first set of data and the second set of data. In one configuration, the age detector includes a controller to determine an age of the memory block, based on the comparison.