The Classic History
Were Adam and Eve the first humans?
The classic response to this question is, of course, yes, that's exactly what the Bible says and why would you believe anything else? I also tend to accept this version of the interpretation of Genesis 1-2 as correct in general. Adam and Eve were certainly the first two humans who had any significance to our modern history. After all, there are many other supporting verses in the Bible you must think about if you don't believe this including Genesis 5:1; 1 Corinthians 15:22,45; 1 Timothy 2:14, to say nothing of the lineage of Jesus Christ as recorded in two gospels.
Other Prehistoric Times
If you look at the When was the beginning? question I have posted, however, there are a lot of questions that need to be considered. In it, I give reasons why I believe that Lucifer reigned on Earth before Adam and Eve were around, why I believe the Earth is just as old as the scientists believe it to be, and why I believe the fossil record is correct. So please read it to answer those questions if you haven't done so yet.
I'll summarize just a couple of Adam and Eve related questions from that text. Since I don't believe that God falsified the fossil record, then mankind, and specifically homo sapiens sapiens existed in the fossil record starting around 200,000 to 300,000 years ago, with some predecessors in the 550,000 to 750,000 year range, it is clear that there were humans who existed before Adam and Eve so clearly they weren't the first. But according to the fossil record, there was a cutting off point that occurred some 30,000 to 12,000 years ago that wiped out all of the other hominids at around the same time. If you look at a graph of their development with the first on the left branching out with all the variations toward the right, at about this time in history all get cut off and homo sapiens sapiens continues on to today.
As I note in the linked article, I think this happened when Lucifer was judged for trying to usurp God's position. It was particularly destructive for Earth, leading to the need to recreate living things as recorded in Genesis 1. This included Adam as seen in the tail end of Genesis 1 and following into the end of Genesis 2 where Eve is created. The Bible doesn't record just how long the Garden of Eden period existed so this fits in with the fossil record if we assume they behaved for a long time and didn't fall immediately. It's also possible that the time period between Adam and Eve's creation was long, so there weren't any human offspring for a long time. All perfectly possible and in concert with the fossil record and the Bible. After all, there aren't a huge number of fossilized humans to account for in the fossil record. There is just evidence based on dating of a very few particular specimens preserved with the dated ages.
You can also speculate on other related questions. In the tribulation, there will be many people who survive the tribulation period and enter into the millennial period. After all, the angels will be preaching from the heavens trying to get people to repent and accept Christ as Savior. I'm not sure how many there will be as the Bible gives lots of reasons why people will have their hearts hardened and will not want to accept Christ. The Anti-Christ killing all Christians found is certainly one big reason. But lets assume that there will be some who are alive at the end and enter the millennium. Could this have happened after Lucifer's judgment and God's first destruction of Earth? These people would have been followers of Lucifer already, engaged in his rebellion, so even when Adam and Eve were created, any remaining people who survived Lucifer's rebellion's judgment would not have been in a sinless state. This is at least consistent with the scriptures above, and could account for the civilization that appears to exist shortly after Adam and Eve are expelled from the protected garden of Eden where they were initially placed.
This last paragraph is purely speculative, and just thrown out for discussion. I don't think it really represents any conflicts with scripture if modern man was created in Adam and Eve, even if they were similar to others. I do stand by the earlier paragraphs though. The earth and universe is really, really old. And so is God.