The age entry notes the age when a member of the race is considered an adult, as well as the race's expected lifespan. This information can help you decide how old your character is at the start of the game. You can choose any age for your character, which could provide an explanation for some of your ability scores. For example, if you play a young or very old character, your age could explain a particularly low Strength or Constitution score, while advanced age could account for a high Intelligence or Wisdom.