Deppends... How old is Earth?
Well, tracing the development of the universe back according to the currently observed laws of physics, we get an age of about 4.5 billion years.
But when we ask "Did God create the Earth/Universe/Mankind", we also bring up the question "How far back, and to what degree, can we trust that the laws of physics currently observed have been valid?"
That is not a question answerable by science, which depends on consistently valid laws of physics to be able to say anything about the past.
Religion generally claims that the supernatural can interact with the natural, which, if true, implies that the currently observed laws of physics are not universally valid (though they may be arbitrarily close to being so within the physical universe if supernatural forces do not often interfere, or generally do so in small ways).
Religious answers to the age of the Earth question depend on religion and interpretation of a religions scriptures, but for Christianity:
If the years given for peoples lifespans and various events in the Bible are historical, mankind is about 6 or 7 thousand years old. There is indication in Genesis that for the first 2000 of those years human lifespans were an order of magnitude longer than at present, which implies drastic divine interference on some level or other, which, if true, brings into question our ability to trust the laws of physics further than 4 or 5 thousand years back.
The creation account in Genesis, if read with "day" meaning "day", and not being symbolic for some longer length of time, indicates that the Earth is about as old as humanity, which, with the previously given approximate age for humanity according to the Bible, means that the Earth is also approximately 6000 or 7000 years old.
However, this is one of the parts of the Bible where I'm not quite sure how it was meant to be interpreted.
Some parts (such as the Gospels) were obviously meant to be read as historical accounts (you may argue if you wish as to whether they were totally made up: The point is that if they are fabrications, they are fabrications meant to look like historical accounts, and if they are not fabrications, they are historical accounts).
Other parts of the Bible (such as the book of Revelation) are fairly obviously meant to be symbolic (Revelation talks about the fall of Babylon, which had already happened long ago by the time the book was written, in order to say something about a future event that will be like the fall of Babylon).
With the creation account in Genesis, I'm not quite sure. It certainly says that God created the Heavens and the Earth (which is an old fashioned way of saying "The Earth and the rest of the Universe").
Being a Christian and believing the Bible is true, I can thus say that I believe mankind to be about 6000 or 7000 years old, and the Earth to be somewhere between that and 4.5 billion years old (with the most likely ages in that range being the endpoints).
I personally don't find O'Reilly's statement here to be too facepalmish. It's not particularly useful or intellectually robust, but I've heard much, much worse from Young Earth Creationists. Sometimes they will try to make scientific arguments for Young Earth Creationism. *That* is facepalmworthy, as science only covers what we can know *naturally*, and cannot say a thing about whether anything supernatural exists or not.