There are several theories that soud reasonable to me, and one that I really think is the most realistic. The most realistic one for me is young earth creationism. i do believe that the genesis account is literal, and i think that the world was created in 6 days, as in 144 hours. I also believe that on the seventh day god rested, not because he needed to but because he wanted us to follow his example. I don't know all of the math, but other people estimate that the earth is 6000 years old if this is true, and that sounds reasonable to me. A lot of things are explained by the flood, and alot of things that evolutionists think they have proof of are created by the flood.
Now my other little theory is that when God created the world, he built history into everything, and that is why evolutionists think that the earth is so much older than I do. You see, i can't imagine a world that is brand new. There has to be history forv the world to exist. take rocks for example. You can't have a new rock. What would that look like? I believe that God created the world and built history into everythig. now the only downside to that is that it makes people think that the earth is a whole lot older than it actually is.
God has given us an amazing world that we have completely ruined in so many ways. But god is so great that he made a world so beautiful that even our enormous stupidity couldn't completely waste it. God is amazing, and I, when it comes down to it, don't even really care how he created this earth. He did, and I have total faith that he knew what he was doing and i think that we should trust him, consider he's perfect, and we're idiots.