1. A mirror comprising: a glass reflecting portion mounted to a stand; a time-of-flight (TOF) camera, a center of a lens of the TOF camera aligns with a top edge of the reflecting portion; a driving apparatus to adjust a location of the reflecting portion on the stand, for changing a height of the mirror; a processing unit; and a storage unit connected to the processing unit, the TOF camera, and the driving apparatus, and storing a plurality of programs to be executed by the processing unit, wherein the storage unit comprises: a three dimension (3D) building module to build a 3D model according to an image of a scene captured by the TOF camera and data about distances between a plurality of points in the scene and the TOF camera; a facial detection module analyzing the 3D model to locate a face region therein; a first location determination module to obtain a first midline between a reference eyeline in the face region and a top edge of the face region; a second location determination module to obtain a second midline of the 3D model; a comparison module to compare the first and second midlines to determine whether the first and second midlines overlap, and output a comparison signal upon the condition that the first and second midlines do not overlap; and a control module directing the driving apparatus to move the reflecting portion relative to the stand according to the comparison signal.