"Then the LORD said to Cain, "Where is Abel your brother?" He said, "I do not know; am I my brother's keeper?" And the LORD said, "What have you done? The voice of your brother's blood is crying to me from the ground. And now you are cursed from the ground, which has opened its mouth to receive your brother's blood from your hand. When you work the ground, it shall no longer yield to you its strength. You shall be a fugitive and a wanderer on the earth."
Cain said to the LORD, "My punishment is greater than I can bear. Behold, you have driven me today away from the ground, and from your face I shall be hidden. I shall be a fugitive and a wanderer on the earth, and whoever finds me will kill me."
Then the LORD said to him, "Not so! If anyone kills Cain, vengeance shall be taken on him sevenfold." And the LORD put a mark on Cain, lest any who found him should attack him.
Then Cain went away from the presence of the LORD and settled in the land of Nod, east of Eden. Cain knew his wife, and she conceived and bore Enoch. When he built a city, he called the name of the city after the name of his son, Enoch." (Gen 4:9-17)

After you re-read Genesis 1 and 2 and have (hopefully) come to a decision as to the day on which Adam was created, and faced the implications of your decision, let us have a look at Genesis 4 and ask a few more questions.

In Genesis 4, we find Cain murdering Abel and being cast away from the presence of God, with a curse placed on his head:
"When you work the ground, it shall no longer yield to you its strength. You shall be a fugitive and a wanderer on the earth." (Vs 12) Cain complaints about his punishment, repeating what God said and its consequences, saying:
"My punishment is greater than I can bear. Behold, you have driven me today away from the ground, and from your face I shall be hidden. I shall be a fugitive and a wanderer on the earth, and whoever finds me will kill me." (Vs 14)

Now, let us ponder this for a while. What are the implications of Cain's assumptions ?
1. There are people out there, on the earth, that he might encounter.
2. These people will be after his life.

Additionally, the following questions arise:
3. Who are these "people" that Cain might meet ?
4. How would they recognize him for someone worth killing ?

In order to prevent anyone from attacking Cain, God puts a mark on him (vs 15) and promises a sevenfold vengeance on anyone who kills Cain. So AFTER God puts His mark on Cain, he should be recognizable as someone you are not supposed to kill. So the answer to question #4 cannot be "Cain has a mark".

If you answer these questions, make sure your answers do not contradict your decisions made after re-reading Genesis 1 and 2. Do you have to jump through a lot of hoops to come to a decision ? Assume a lot of things to "make things fit" ? If that's the case, you probably need to re-think your reading of Genesis 1 and 2, and get ready to believe God and accept what the bible says at face value.

And one last question to consider:
5. If Cain is hidden from God's face while wandering the earth, are the people he encounters hidden from God's face too ?

When it comes to the Scriptures, Mark Twain's remark applies in an interesting way:

"It is not what you do not know that will hurt you the most. It is what you think you know, but it just ain’t so!"