yeah, but the thing is other religions (which are also older) have stories of a great flooding or disaster as well which are attributed to their god/s. so why would christianity take precedence over those religions.
heres a few
Africa
Southwest Tanzania
Once upon a time the rivers began to flood. The god told two people to get into a ship. He told them to take lots of seed and to take lots of animals. The water of the flood eventually covered the mountains. Finally the flood stopped. Then one of the men, wanting to know if the water had dried up let a dove loose. The dove returned. Later he let loose a hawk which did not return. Then the men left the boat and took the animals and the seeds with them.
Asia
China
The Chinese classic called the Hihking tells about "the family of Fuhi," that was saved from a great flood. This ancient story tells that the entire land was flooded; the mountains and everything, however one family survived in a boat. The Chinese consider this man the father of their civilization. This record indicates that Fuhi, his wife, three sons, and three daughters were the only people that escaped the great flood. It is claimed, that he and his family were the only people alive on earth, and repopulated the world.
Babylon
Gilgamesh met an old man named Utnapishtim, who told him the following story. The gods came to Utnapishtim to warn him about a terrible flood that was coming. They instructed Utnapishtim to destroy his house and build a large ship. The ship was to be 10 dozen cubits high, wide and long. Utnapishtim was to cover the ship with pitch. He was supposed to take male and female animals of all kinds, his wife and family, provisions, etc. into the ship. Once ship was completed the rain began falling intensely. The rain fell for six days and nights. Finally things calmed and the ship settled on the top of Mount Nisir. After the ship had rested for seven days Utnapishtim let loose a dove. Since the land had not dried the dove returned. Next he sent a swallow which also returned. Later he let loose a raven which never returned since the ground had dried. Utnapishtim then left the ship.
Chaldean
There was a man by the name of Xisuthrus. The god Chronos warned Xisuthrus of a coming flood and told him to build a boat. The boat was to be 5 stadia by 2 stadia. In this boat Xisuthrus was to put his family, friends and two of each animal (male and female). The flood came. When the waters started to recede he let some birds loose. They came back and he noticed they had mud on their feet. He tried again with the same results. When he tried the third time the birds did not return. Assuming the water had dried up the people got out of the boat and offered sacrifices to the gods.
India
A long time ago lived a man named Manu. Manu, while washing himself, saved a small fish from the jaws of a large fish. The fish told Manu, "If you care for me until I am full grown I will save you from terrible things to come". Manu asked what kind of terrible things. The fish told Manu that a great flood would soon come and destroy everything on the earth. The fish told Manu to put him in a clay jar for protection. The fish grew and each time he outgrew the clay jar Manu gave him a larger one. Finally the fish became a ghasha, one of the largest fish in the world. The fish instructed Manu to build a large ship since the flood was going to happen very soon. As the rains started Manu tied a rope from the ship to the ghasha. The fish guided the ship as the waters rose. The whole earth was covered by water. When the waters began subsiding the ghasha led Manu's ship to a mountaintop.
Australia
There is a legend of a flood called the Dreamtime flood. Riding on this flood was the woramba, or the Ark Gumana. In this ark was Noah, Aborigines, and various animals. This ark eventually came to rest in the plain of Djilinbadu where it can still be found. They claim that the white mans story about the ark landing in the middle east is a lie that was started to keep the aborigines in subservience. This legend is undoubtedly the product of aboriginal legends merging with those of visiting missionaries, and there does not appear to be any native flood stories from Australia.
Europe
Greece
A long time ago, perhaps before the golden age was over, humans became proud. This bothered Zeus as they kept getting worse. Finally Zeus decided that he would destroy all humans. Before he did this Prometheus, the creator of humans, warned his human son Deucalion and his wife Pyrrha. Prometheus then placed this couple in a large wooden chest. The rains started and lasted nine days and nights until the whole world was flooded. The only thing that was not flooded was the peaks of Mount Parnassus and Mount Olympus. Mount Olympus is the home of the gods. The wooden chest came to rest on Mount Parnassus. Deucalion and his wife Pyrrha got out and saw that everything was flooded. They lived on provisions from the chest until the waters subsided. At Zeus' instruction they re-populated the earth.
North America
Mexico
The Toltec natives have a legend telling that the original creation lasted for 1716 years, and was destroyed by a flood and only one family survived.
Aztec- A man named Tapi lived a long time ago. Tapi was a very pious man. The creator told Tapi to build a boat that he would live in. He was told that he should take his wife, a pair of every animal that was alive into this boat. Naturally everyone thought he was crazy. Then the rain started and the flood came. The men and animals tried to climb the mountains but the mountains became flooded as well. Finally the rain ended. Tapi decided that the water had dried up when he let a dove loose that did not return.
United States
The Ojibwe natives who have lived in Minnesota USA since approximately 1400AD also have a creation and flood story that closely parallels the Biblical account. "There came a time when the harmonious way of life did not continue. Men and women disrespected each other, families quarreled and soon villages began arguing back and forth. This saddened Gitchie Manido [the Creator] greatly, but he waited. Finally, when it seemed there was no hope left, Creator decided to purify Mother Earth through the use of water. The water came, flooding the Earth, catching all of creation off guard. All but a few of each living thing survived." Then it tells how Waynaboozhoo survived by floating on a log in the water with various animals.
Ojibwe - Ancient native American creation story tells of world wide flood.
Delaware Indians - In the pristine age, the world lived at peace; but an evil spirit came and caused a great flood. The earth was submerged. A few persons had taken refuge on the back of a turtle, so old that his shell had collected moss. A loon flew over their heads and was entreated to dive beneath the water and bring up land. It found only a bottomless sea. Then the bird flew far away, came back with a small portion of earth in its bill, and guided the tortoise to a place where there was a spot of dry land.
South America
Inca
During the period of time called the Pachachama people became very evil. They got so busy coming up with and performing evil deeds they neglected the gods. Only those in the high Andes remained uncorrupted. Two brothers who lived in the highlands noticed their llamas acting strangely. They asked the llamas why and were told that the stars had told the llamas that a great flood was coming. This flood would destroy all the life on earth. The brothers took their families and flocks into a cave on the high mountains. It started to rain and continued for four months. As the water rose the mountain grew keeping its top above the water. Eventually the rain stopped and the waters receded. The mountain returned to its original height. The shepherds repopulated the earth. The llamas remembered the flood and that is why they prefer to live in the highland areas.