1) Does it allow you to have messengers such as Skype, MSN, Aim, or Yahoo?
We have multi-chat clients, you get all those except maybe skype in one. Skype also works in linux.
2) If it worth the downloading?
If you like computers, yes.
3) Will I be able to use Google Chrome on Ubuntu
Yes, but I recommend chromium-browser, as it is the free version of chrome, and most likely what you will find in linux.
4) Should I change my operating system or should I stick with Windows?
Test linux on a usb drive. You can boot off the usb drive and be in linux. When you shut down and remove the usb drive it will restart into whatever you have currently.
5) I have Big Fish Games will I lose that?
I don't know what that is.
6) Will I still have Avast anti virus?
You can, they have a linux version, but it's terrible. Use clamav if you need to scan something. Sticking to the supplied repositories from your distribution means an incredibly insignificant chance that you will download malware. The only thing you have to worry about is java and other cross platform problems that effect everybody.
7) Will I have to re install anything like for example a printer?
If you use a debian based os (debian/ubuntu/mint) then setting up printers is quick and easy. I can setup a network printer on linux faster than on windows.
8) I have a HP will that change anything on me getting Ubuntu?
I don't think so. Normally you only have to worry about anything with a 'broadcom' wireless chipset. Also there are new graphic cards, something like 'optimus' that are a problem. If you don't have either of these, then it should be relatively smooth sailing.
Make yourself a live USB and boot into linux a few times. Give it a fair chance, and a live usb is a great way to surf the web safely, as nothing is saved, each reboot is like the first time.