https://answersingenesis.org/bible-timeline/genealogy/did-adam-and-noah-really-live-over-900-years/

Here's a good article on the ages of people pre and post flood. According to this analysis, people lived past 120 years after the flood, but life expectancy declined over time. One could argue this is plausible as genetic stochasticity negatively affected lifespan given the world had to 're-populated by Noah and his followers, but there is a potential snag in minimum viable population to avoid extinction given there were supposedly only 8 people on the ark according to 1 Peter 3:20. If you think Adam and Eve were enough to first populate the Earth, then Noah 's group would likely also have no problem.