I've just emerged xorg-x11 and afterwords, it said "2 configuration files in /etc need updating". I'm new to linux so I wasn't sure what to do but I saw that you're supposed to run "etc-update" when this happens. So, the first configuration file that needed updating came up so I looked at it but wasn't sure what to do (whether I should replace the original or not), so I hit "-1" to ignore the update thinking I'd simply be able to return to it later in order to decide what to do. Now, whenever I run etc-update however, it just shows the next file that needs updating and I can't get back to the first one. I'm worried that I should have updated it and I don't even remember what file it was. Is there a proper solution to this?

Possibly. The first thing to do is complete your LQ profile with at the very least the distro you are using.