Average girl's weight in Japan and Vietnam
15 years old
Japan is 51.7 kg
Vietnam is 39.66 kg
16 years old
Japan is 52.7 kg
Vietnam is 41.69 kg
17 years old
Japan is 53.0kg
Vietnam is 43.39 kg

Source
Vietnam
https://huemed-univ.edu.vn/chieu-cao-dung,-can-nang-va-chi-so-khoi-co-the-cua-thanh-thieu-nien-15-den-24-tuoi-o-thua-thien-hue-sckhcn-c74
Japan
https://www.mext.go.jp/content/20200319-mxt_chousa01-20200319155353_1-3.pdf