The statement “a thousand years is as one day” is just a way of stating that God is outside of time - therefore billions of years are of no greater consequence to Him than billions of miles. To believe that the earth is only
6000 years old requires one to discard overwhelming scientific evidence to the contrary. I believe in a literal Adam and Eve but will not try to establish a date.
Patience.
I have a hunch many things could be revealed very soon.
1. The scientific evidence is underwhelming. There is an large body of observations that have been organized into a massive number of just-so stories that are used to support what has become the religious dogma of the scientific community. Those same observations fit better with a young earth and a world-wide flood.
2. Basing your interpretation of Genesis on a convenient but unrelated verse in 2 Peter is sloppy hermaneutics. If you want to use verses in 2 Peter to help understand Genesis, use 3:5-6. Verses 7-8 are talking about the coming judgement, not the past one.
3. I’m not locked in to 6000 or so years. While the pattern in in the Genesis geneology is “A lived __ years and begot B... B lived __ years and begot C”, etc., I do think some of the steps could contain more than one generation - B might be C’s great-great-grandfather, rather than his father, and C might just be the next significant person in the line. But I think the actual age of the earth is a lot closer to 6K than 1B years.
Well, first of all, there is evidence in the Scripture that the creation of Adam and Eve was the beginning of an age, and that there were other ages before the time of Adam and Eve and the earth itself is actually billions of years old. The Bible also talks about a "great animal, called “behemoth,” which "bends it's tail like a cedar" and with which Job was familiar and can be found in Job 40:15-24, which throws some real doubt on evolutionist theory.
There is also evidence in Scripture that the earth was "without form and void" after Satan had his rebellion against God and God, after this rebellion, renewed the earth and rebuilt it just as the Bible says He will do after the thousand year Millennial Kingdom.
Second, it's not real smart, as a fallen human being with extremely limited knowledge about what went on before we were born, to declare that when God said He created the earth in six days, and then later states that a day to him is as a thousand years, that that statement simply isn't true. I think it's wiser, due to the fact that we have no way of knowing all the angles and all the facts, just to take God at His word and believe what He says.