My friend who is 73 commented she has lived longer then God had promised us.She states that in psalms some where it says 70 ad that after that you can pray for more years and if you have obeyed and lived a righteous life you can ask for more years. I know we are not promised our next breath and no one really knows how many years we have, yet I was thinking God said 120 years in Gen6:3. Who is right?
In a way you are both right. Genesis 6:3 says, “And the LORD said, My spirit shall not always strive with man, for that he also is flesh: yet his days shall be an hundred and twenty years.” Psalm 90:10 says, “The days of our years are threescore years and ten [70 years]; and if by reason of strength they be fourscore years [80 years], yet is their strength labour and sorrow; for it is soon cut off, and we fly away.”
Before the passage in Genesis we find people who lived hundreds of years. After that time life spans went down to about 120 years. By the time the Psalms were written, the average life span was considerably less than 70 years, with that number being considered a good old age. Of course, that was about 3000 years ago. Increases in medical and nutritional knowledge have allowed us to live to a life expectancy of about what the Psalm says, with an upper limit well under the 120 years of Genesis.
Does that make the Bible wrong? Not at all! For the times when those passages were written, the life expectancy given was a good figure. For this time the 120 year figure is quite high, but the 70 to 80 year figure may be low. If David were writing the psalm now, he might raise the figure a little.
We should just praise God that he has given us the knowledge to live longer than previous generations. As you point out, though, we should also be aware that not everyone will live to the life expectancy figures anyone may give. We should be ready and eager to meet God at any time.
Note: For a different, and possibly more correct, perspective on the Genesis 6 passage, see my answer at What Does the Bible Say About..120 Years?