Verse 5 For this they willingly are ignorant of, that by the word of God the heavens were of OLD, and the earth standing out of the water and in the water: (Genesis 1:2) Peter is NOT talking about Noah's flood, as he already instructed the subject of Noah's flood back in Chapter 2 and had NO difficulty in using Noah's name to tell the reader the 'time' frame. And unless the reader has read with understanding the Genesis 6 account as to WHY God sent a flood, and WHY Noah and his family were 'elected' to be saved from that particular flood then they are willingly ignorant.
Verse 6 Whereby the world that then WAS, being overflowed with water, perished:
Verse 7 BUT the heavens and earth which are NOW, by the same word are kept in store, reserved unto fire against the day of judgment and 'perdition' of ungodly men.
Verse 8 BUT, beloved, BE NOT ignorant of this one thing,
that one day is with the LORD as a thousand years, and a thousand years as one day.... (How many 'days' of creation were there???)
How long did Methuselah live, not quite ONE day with the LORD.
But you have not shown how specifically. You have simply regurgitated futurist pap.
There's nothing about "creation days" or Methuselah in the passage. That's your pap. You are assuming stuff that is not there.