In Genesis 7:6 we read Noah was 600 years old when the flood landed.
Only four verses later we read he'd been in his 600th year when the flood began.
Why would the author write of the events in that order and give the same age twice in this way?
Gen 7:6-11, KJV:
And Noah was six hundred years old when the flood of waters was upon the earth. And Noah went in, and his sons, and his wife, and his sons' wives with him, into the ark, because of the waters of the flood. Of clean beasts, and of beasts that are not clean, and of fowls, and of every thing that creepeth upon the earth, There went in two and two unto Noah into the ark, the male and the female, as God had commanded Noah. And it came to pass after seven days, that the waters of the flood were upon the earth. In the six hundredth year of Noah's life, in the second month, the seventeenth day of the month, the same day were all the fountains of the great deep broken up, and the windows of heaven were opened.