The preponderance, though not all, of the scientific evidence points to an old universe and to the existence of macroevolution. However, both the creation science and intelligent science camps have pointed out deficiencies in evolutionary theory that the evolutionist camp has not successfully refuted. However, the conservative Christian position is not necessarily based on what camp has better evidence. Conservative Christianity works from the presupposition that the statements in the Bible are true, when understood in their historical and grammatical context and authorial intent. Based on that assumption, evangelicals and fundamentalists must reject the presumption that mainstream science adheres to: that the physical universe is all that was, is, and ever will be.
The ultimate issue is not what the fossil record, astronomy, DNA, half-lives of elements, etc., may or may not indicate. The issue is which worldview is correct: the conservative Christian one, the naturalistic one, a position that synthesizes the two positions, or another one entirely.
So what? That's not relevant to the scientific process, which is based on what camp has better evidence. You're trying to take tools from one arena and use them in an entirely different arena - what you're essentially doing is trying to bake a cake with a belt sander, and wondering why the results are such a mess.