There is something very important we must remember when it comes to the age of the earth.
originally all of creation was credited to being created by God .... and the best date we could come up with was 6000 years old according to the genealogy of the bible.
It was only when the secular world (non-creationists) began promoting their evolutionary theory that people started to use millions of years to date the earth.
Then even Christians started to bump up their dates ..... WHY ??? .... they did it to appease the non-creationists .... it serves no other purpose. !!!!!!!!!
God does not require long periods of time to create anything
An example ..... Making and fermenting wine takes time ... yet Jesus did it in an instant at the wedding.
Now the "serious" issue
According to God ..... do you know what the biggest sin is ?
It is not recognizing The Creator and creation as being entirely done by God ..... anyone who does not recognize this is venturing into dangerous territory ..... read this carefully ...
The wrath of God is being revealed from heaven against all the godlessness and wickedness of people, who suppress the truth by their wickedness, since what may be known about God is plain to them, because God has made it plain to them. For since the creation of the world God’s invisible qualities—his eternal power and divine nature—have been clearly seen, being understood from what has been made, so that people are without excuse.
For although they knew God, they neither glorified him as God nor gave thanks to him, but their thinking became futile and their foolish hearts were darkened. Although they claimed to be wise, they became fools and exchanged the glory of the immortal God for images made to look like a mortal human being and birds and animals and reptiles.
Therefore God gave them over in the sinful desires of their hearts to sexual impurity for the degrading of their bodies with one another. They exchanged the truth about God for a lie, and worshiped and served created things rather than the Creator—who is forever praised. Amen.
Because of this, God gave them over to shameful lusts. Even their women exchanged natural sexual relations for unnatural ones. In the same way the men also abandoned natural relations with women and were inflamed with lust for one another. Men committed shameful acts with other men, and received in themselves the due penalty for their error.
Furthermore, just as they did not think it worthwhile to retain the knowledge of God, so God gave them over to a depraved mind, so that they do what ought not to be done. They have become filled with every kind of wickedness, evil, greed and depravity. They are full of envy, murder, strife, deceit and malice. They are gossips, slanderers, God-haters, insolent, arrogant and boastful; they invent ways of doing evil; they disobey their parents; they have no understanding, no fidelity, no love, no mercy. Although they know God’s righteous decree that those who do such things deserve death, they not only continue to do these very things but also approve of those who practice them.
Summary ..... not recognizing God and His creation is the greatest sin .... and when mankind does that ..... then He gives them over to do all the other 'terrible sins" like murder , hate , sexual depravity.
The Christian would be wise not to ignore Gods record of creation in Genesis ..... when we move away from that , we are joining with the unbelieving secular evolutionists who claim that the world made itself over a long period of time.