Original sentence: Gyeong Dae-seung died at the age of 30 during the year 1183.The young Gyeong began his military training at the age of 15, and served under the regimes of both Yi Ui-bang and Jeong Jung-bu
Edited sentence: Gyeong Dae-seung died at the young age of 30 during the year 1183.The young Gyeong began his military training at the young and tender age of 15, and served under the regimes of both Yi Ui-bang and Jeong Jung-bu