Death

They all think that until the Flood came. And you're here just like them.

You can mock, but when that day comes, it will preceded by a literal hell on earth which we call, the "Tribulation Period" (Matthew 24:6-8, 21, & 29-30).

So if you lived and died before that period, it is no proof of your premise but only physical mercy as you were spared of it. Then again, it will be the only tangible prood of God you will ever experience.