Thanks for your question.
Here are some passges which deal with Noah and the ark: Genesis chapters 6-8; Matthew 24:37,38; Luke 17:26,27; 1 Peter 3:20; 2 Peter 2:5.
In Genesis 6:3, the 120 years mentioned does not refer to a person's average lifespan but rather God was saying: "Man's days are numbered. He has 120 years left until the flood comes."
God bless,
Mike
thisisyourbible.com