Predicted H-peak at lower metallicity has a lower brightness at a given time. The shift in the H-peak position can be explained by the shift in the evolutionary tracks with metallicity. As the metallicity becomes lower, the stars of the same initial mass become hotter and brighter. Therefore, given the same initial mass, the lower metallicity stars evolve faster on the pre-main sequence; at the same evolutionary stage, the critical points on the evolutionary tracks of lower metallicity represent a star with a lower mass and brightness. The lower metallicity population undergoes the critical phases earlier, shifting the H-peak–age relation to the lower age end.