This scripture proves that Christ existed at the time of the flood.

"Having been put to death indeed in the flesh, however, being made alive in the spirit, in which also to the spirits in prison he went to preach when they were disobedient; while God was waiting in longsuffering in the days of Noah for the ark's construction." 1Pt 3:18-20 (Joshua)

Jesus was put to death at the end of His ministry.

He was resurrected as a spirit after three days.

Jesus was also a spirit when He went to preach to the angels before the flood, that were disobedient during that time, but who are now in prison.

And Jesus preached to these angels during the 120 years Jehovah waited for the construction of the Ark.

Joshua