The proper answer is that the Bible does not give us the age of the earth, so we don't know for sure.
What we do know is that God told us that He created the heavens and the earth, and that He did it in 6 days, with a day of rest following. He said that all that He created was "good" and when He created humans (male and female) He said that His creation was "very good." this "very good" earth was cursed by God when mankind entered into sin against God. All that we (and science) observes post-fall into sin, is an observation that is not of the original "very good" universe and earth, which may lead to conclusions that are not completely valid concerning the age of the universe, the age of the earth, or some of the tenets of science that indicate such.
We tend to see the age of the earth as much younger than current science would dictate, and we both use the same evidence to arrive at our conclusions.
We feel that the scientific observational data that points to the universe having an "actual" beginning is nothing more than an observation of God's creative effort. God said, "let there be light" and "light" is what scientists who study our cosmos have discovered. The universe, by nature, "must" have a beginning, or else it would be an actual infinite, and such is actually impossible. The discussion of why goes beyond the scope of this short post, but it involves trying to add a number to an already infinite amount of numbers, making things like time meaningless.
We agree with the science that points out certain anthropic principles that indicate that our entire universe, and our earth were both very finely tuned for human habitation. Over 130 of these anthropic principles have been discovered and the probability of any one of them coming about by chance are far less than impossible. The probabilities for the fine-tuning of the universe far exceed the total number of particles in the universe to a range in excess of 10X10 to the 125th power (multiply 10 x 10, 125 times or more) for each of the principles measured by science. These include things like the weak and strong nuclear force, the space between electrons, the amount of gravitation, the amount of energy in the universe, the rate of expansion, the distance between moon and earth, other planets, the earth and sun, the solar system to other stars, galaxy to other galaxies, etc.
We agree that all things reproduce according to "kind" which is now confirmed via the study of DNA and genetics. We agree that we are "fearfully and wonderfully made" and as the science of micro-biology expands and new discoveries are made, the extent of that phrase is mind-boggling. The machines that work in the inner parts of each cell are sophisticated and inter-active in a way that virtually tosses any evolutionary tenet out the window as being untenable.
Finally, we agree that there are more ways of "knowing" than mere scientific experiment, and that, in large part, most science involved in the study of the cosmos is not derived from "experiment" but rather from applied logic and philosophy based on inference and observation -- in other words, metaphysics (religion). We can know by evidence, by observation, by testimony, and by inference of truthful propositions, and we do know that there is no scientific experiment that can possibly answer the question, "Why are scientific experiments the only sure way of "knowing." That issue is derived from philosophy, not observation or experiment.
