Accounts setup

I am the only one who uses my Mac (I'm not sharing with anyone). I've noticed something in the get info window of finder. For all or most of my files, In the box at the bottom regarding sharing and permissions, there are three entries:
"Christopher (Me)"
"admin"
"Everyone"

I'm the administrator for my computer, obviously. Why are there three names instead of two? (I am after all the administrator) Now, I was looking around the advanced section of the accounts window in System Preferences, and I was fooling with the short name for the account. It used to be chrislandalusa, but I changed it to the Name above. I was going through my OS X manual and created some temporary standard accounts to see how it was done, but deleted them immediately. I don't know if that infor makes a difference, but I'm including as much as I can remember, because I'm beginning to wonder if I've messed something up or not. All the files/folders I've created are still there and I can get to everything. I just want to know why I have an extra name in the permissions list and if so, if I can get rid of one. Is "Christopher" different from "admin" (at least as far as the computer is concerned) -- because when I open the System Preferences window and click on the Accounts Pane, all I see is Christopher, which is the admin account and what the computer automatically logs into. And what is "everyone?"

admin is likely a group, although on my box it shows 'staff'.

admin is a group, of which you are a part if you are an admin of the system

Everyone is also a group, that all other users would be a part of.

No, you do not want to do anything to "get rid of them".

Christopher is not really the "admin" account. Christopher is a user account with admin privileges.

From what you've described, I doubt very seriously that you have messed anything up.

It all gets much more technical and my mind is fried. There really is not any point that I've seen for a regular user to be concerned with permissions or have all that stuff running around in your head on a Mac except to run "Repair permissions" on occasion.