A careful reader of the Scriptures thinks that the KJV does not follow the Greek in Matthew 28:20 in reporting Jesus’ promise to his apostles “I am with you always, even unto the end of the world” (and so in the ASV). She thinks that the NIV is more correct: “I will be with you always, to the very end of the age.”
The NIV translation of the Greek is accurate, and so are the translations of the KJV and the ASV. Jesus’ word aion means “age” and also “world” or “universe,” as seen in the NIV translation of aion in Romans 12:2, “Do not conform any longer to the pattern of this world”; and in Hebrews 1:2, of what God did by Jesus, “through whom he made the universe” (NIV); and in Hebrews 11:3, “By faith we understand that the universe was formed at God’s command” (NIV).
Thayer (p. 19) cites the double usage of aion. Abbott-Smith (p. 15) says that kosmos, “the ordered universe,” is a synonym for Jesus’ word aion.
Scripturally, no age follows our present age: on “us” is “the fulfillment of the ages has come” (1 Corinthians 10:11, NIV), “the ends of the world are come” (KJV). Christ has appeared “at the end of the ages” (Hebrews 9:26, NIV), “in the end of the world” (KJV). After “the end of the age” is not another one on this planet, but then comes the “harvest,” and “the harvesters are angels” (Matthew 13:39, NIV), when “the weeds are pulled up and burned in the fire, so it will be at the end of the age” (Matthew 13:40, NIV), “in the end of this world” (KJV). Jesus said, “This is how it will be at the end of the age. The angels will come and separate the wicked from the righteous” (Matthew 13:49, NIV), “at the end of the world” (KJV).
Because some might infer that there is to be another age after our present age before the end of the world, it is better to stick with the KJV and the ASV translations of Matthew 28:20.