In this study, the effect of the eSports player's age on the performance in four major regional leagues of League of Legends (LCK, LPL, LEC, and LCS) was investigated from spring 2016 to summer 2020. On average, League of Legends eSports players in the four major leagues averaged 20.7 years old, and most players were between the ages of 18 and 22. Their winning rate and performance increase with age, peaking at the age of 20 and then gradually decrease. For the performance of each position, Top and Jungle position peaked at the age of 20, the same as the average aging curve. In the jungle position, the win rate and key indicators decreased the most sharply thereafter, with the lowest average age and the shortest career at the same time. The Mid position showed the best win rate and performance even at a young age without a section in which the win rate or line match index increased according to age, while the Supporter position showed a higher average age and distribution compared to other positions. This study on the effect of the eSports player's age can be great help eSports clubs in their efficient process of recruiting, nurturing, and setting salaries on the rapidly growing eSports market.