I agree with you regarding "Let there be light" referring to the Big Bang. However, it's not unreasonable to assume that there might have been another source of light for these plants to grow. Alternatively, even if there wasn't, do you not think that a God who could create the Sun and the Earth from nothing would be unable to make plants grow without the Sun? It seems that many so-called 'rebuttals' of the Bible try to disprove it by explaining why some events are physically impossible, but what
is impossible to an all-powerful God who created the laws of physics themselves? Is he not able to bend them to His will?
If one tries to nitpick on every little detail in the Scriptures, they will have a lot of occasions to do so. It is quite easy to find apparent contradictions by interpreting the Bible in a way that is suited to your goal. It is not, however, a proof that the Bible contradicts itself, as it relies on a specific interpretation. When it come to religious matters, very few things can be proven or disproven.
The way I see it, Christian faith is about being humble. You can't find God if you read the Bible with a self-righteous, know-it-all attitude, trying to disprove it line by line. I found this[1] page to explain this point of view quite well.
You cannot apply the principles of science to metaphysical matters, because science concerns itself purely with the physical, tangible world, and has no answers to offer regarding its origins, its meaning, etc. Science and faith do not contradict each other; rather, they complement each other. I like to think of myself as a highly rational individual; mathematics and programming, for example, delight me. Yet I have no issue believing that the Bible is true, and that the God of Abraham, Isaac and Jacob is the creator of the Universe. Does that make me a fool? In the eyes of some, yes. Is it possible to be cognitively biased in a specific area yet highly rational in others? Absolutely. But to say that reason precludes faith is simply incorrect.
[1]: http://www.christiananswers.net/q-comfort/contradictions-bib...