I would like to understand how anyone with reason, knowledge of the Bible, and credibility, can put a number on this.
If we believe the Bible, Adam was created, lived in the Garden, and was endowed with eternal life; so long as he was obedient to YHWH. I have found absolutely no Biblical reference for how much time elapsed, from the time that YHWH created Adam, until Adam disobeyed YHWH.
Until I see a number in scripture, any number greater than zero, up to infinity, is a possibility.
Adam and Eve were created immortal. Otherwise, why would there be a tree of the knowledge of good and evil to remind them that if they eat any part of the tree, they will die.
From the time Adam disobeyed, his immortality and youthful look were gone and started to age and deteriorate slowly to death for 930 years.
There's no information how long he had this immortality. However, the Lord told Adam to name all the animals. There are about more than 1-2 million species of animals on Earth. Maybe, it will take him about 80-100 years to name all the animals by himself. Then, here comes Eve who was also immortal.
Both of them were naked and were naturally attracted to each other. If there's attraction, we know what will come next. When they ate the tree of the knowledge of good and evil, Eve shortly became pregnant to twins.
My guesstimate will be 100-150 years before Adam and Even sinned.
No, they were not!!
Gen 3:22 And the LORD God said, Behold, the man is become as one of us, to know good and evil: and now, lest he put forth his hand, and
take also of the tree of life, and eat, and live for ever:
If they had stayed in the garden, with the tree oi life, they would have stayed immortal in sin.
After the resurrection we are again given access to the Tree of Life:
Rev_2:7 He that hath an ear, let him hear what the Spirit saith unto the churches; To him that overcometh will I give to eat of the tree of life, which is in the midst of the paradise of God.
Rev_22:2 In the midst of the street of it, and on either side of the river, was there the tree of life, which bare twelve manner of fruits, and yielded her fruit every month: and the leaves of the tree were for the healing of the nations.
Rev_22:14 Blessed are they that do his commandments, that they may have right to the tree of life, and may enter in through the gates into the city.
1Ti 6:15 Which in his times he shall shew, who is the blessed and only Potentate, the King of kings, and Lord of lords;
1Ti 6:16
Who only hath immortality, dwelling in the light which no man can approach unto; whom no man hath seen, nor can see: to whom be honour and power everlasting. Amen.
Immortality is a gift from God, not a right of birth!!
Rom_6:23 For the wages of sin is death; but the
gift of God is eternal life through Jesus Christ our Lord.
There is no way that Satan would have wasted any time in tempting them to fall. It doesn't say how long they were there.
Not every single species of animal had been created---but each classification of animals. Not every species of Cat---but a male and female of a cat, micro evolution would do the rest. Like when Noah had the animals taken into the ark---they were the parent of the species---not every single species. Noah didn't need 30 different kinds of dogs--just wolves. Microevolution then would create all the different types of dogs. Irish Wolfhounds to Chihuahuas all come from wolves.