Here is a thought to add to this thread to make sense of things. Most of us have seen ideas around the earth being a central land mass with sea all around as like a jigsaw, scientists joined up the pieces, but what is interesting is the pieces also fit in other ways. For example, one can fit the USA to Europe etc, but you also can fit the land mass from USA to Russia and below, especially if Australia is brought up to fit the South America regions etc.
Now the theory I found was that the whole earth used to be much smaller with hardly any sea except four big rivers. It was more like a much smaller ball being nearly all land, and if one looks at each country and continent one can visualise it. (Well I can!)
As to age, as mans equipment is based on theory rather then fact, (It is like drawing a graph with the assumption the results give a straight line between age and carbon content or a similar method where in reality, not only would big events like the flood vastly alter results, previous climates and gravitational effects were vastly different to today so our graph results could be way out!)
The most reliable dating methods so far is written history. We know the Calender's used so can work out written historical records. These we know are a foundation to work from. We can then at least go back to the flood as a guide to calibrating our equipment. The issues are with accuracynis going further back beyond that point.
The Bible gives record (If one goes through the genealogies and works it out with ages of people) to our earth being around 6000 years old or thereabouts. The Bible does not give any indications of millions of years anywhere. Indeed, if one tries to add millions of years (Or more then a few days) into the Genesis account of Creation, it is not possible as certain sections of creation rely on others to be present to survive. It is only by using actual days it all comes together as a workable form.
While I believe in creation, I didn't used to hold a view either way. I used to try to fit evolution into creation and add millions of years here and there but no matter how I tried it, it didnt work, yet when I read it exactly as it says it does work. Everything fits.
At this point I realised that either the whole Bible is true or the whole Bible is a lie. It is this that brought me to realise the Bible is true, as one can't write half truths in such a clever form and call it the Word of God. Others have done that and are always trying to excuse various inaccuracies!
Since also bringing in the spiritual aspect of the Bible, I have only found one single piece in the Bible that has a form of confliction and have looked it up finding it to be a mistake in some translations but no mistakes in the original text. (I'm no expert. I just happen to have access to a comprehensive concordance).
Anyway. Hope I have not gone too far off subject as it is up to the individual to decide how old the earth is for themselves. I will say is to start with an open mind as if you know nothing. Bring in all the various theories you can find (There are many.. Is not just Creation v Evolution!). Weigh them up one at a time and make a decision based on this. Pray before hand that God will lead you to the truth. Yes?