Bible genealogies state that Adam lived about 4000 BC. Many Christians – perhaps most – believe that God created the entire universe, including Adam, in a single six-day period.
That means that nothing – not even dinosaur bones or the sun – are older than about 6,000 years. Most people think that's downright ignorant in light of modern knowledge.
If we say that this is what the Bible teaches, we undermine credibility of the Bible and drive people from Christ.
What most Christians don't know is that the Herew word 'yō·wm' in the original Bible manuscripts, translated 'day' in English versions, can mean either a 24-hour period or a long indefinite period of time (like we sometimes say 'this is the day of social media' and everyone knows from the context that we mean more than a single calendar day).
How do YOU answer the scoffer who says that Christians are stupid for believing that everything came into existence relatively recently, all in the same week?