Moses spent his first 40 years as a prince in Egypt. The next 40 years he spent as a shepherd in Median. That is, when God called him to go back to Egypt and lead the slaves from there to the promised land, he was 80 years old.

Did you know? The book of Exodus chapter 7: 1-7 gives the record of God's command and the reference to the age of Moses and his brother Aaron. (Bible - Old Testament).

This might be interesting: After wandering another 40 years in the wilderness, Moses got to see the promised land but did not cross over with the people. He died at age 120.

More Info: biblehub.com