Predicted and observed age distribution of GCs. The observational data for GCs from the Milky Way, from Kruijssen et al. (2019), and for the massive elliptical galaxy NGC 1407, from Usher et al. (2019) and compiled by Valenzuela et al. (2024), are shown as solid lines. The dash-dotted lines show the predicted age distributions from our simple model, adopting the cosmic SFR density history from Shuntov et al. (2025) for different values of z_min = 1.5, 2, and 3. The dotted line shows the same z_min = 2 and the higher ρ_SFR(z) values inferred from the GLIMPSE survey.