From my understanding of the account in Genesis, God wasn't overly concerned about giving us a science lesson.
As for the age of the earth I don't believe the bible claims he did it in seven literal days.
PTB If the creator knew that his credibility would rest on the record he set, in his claimed word and creation, he would make sure that his works would not contradict his word. imho. He would know, that the truth about the truth aka his word, would come out, sooner or later.
The bible claims that the Earth was created at the Big Bang, . the landscaping came later.