I researched you motherboard is compatible with Linux. Being that you are new to linux I do not think ubuntu is new user friendly as it used to be. I use a distribution called PClinuxOS which is geared to be easier to use as it does not put you though loops when you need a codex to play mp3 files. I use pclinuxos on my t500 IBM laptop.
There are other factors of which to consider...
If you use a printer you will need to check it's
Compatibility. Go to linuxprinting.org and search for your model and brand of printer.
If you transfer music to your phone via windows than that I have not figured out yet on Linux.
Using Linux
Look at guides on the web for the file system structure it is not the same as windows.
PCLOS has two desktop gui KDE and Mate. On older hardware the Mate desktop gui uses less resources that KDE plus you can customize the gui. KDE is more static. By this is mean hiding software from the start menu etc.
As for gaming you will not be able to play windows games on Linux. If you really need to play games.
Here are a few sites to research
https://www.playonlinux.com/en/supported_apps-1-0.html
http://store.steampowered.com/search/#sort_by=_ASC&category1=998&page=1&tags=-1
Myself I have been planing on leaving windows as my primary os and use macs as my primary and my secondary os is pclinuxos. If you decided to try a distribution of linux you can download a isolation image and than burn it to a DVD. Insert the DVD in the system and reboot the live dvd will boot into memory only. It will be slower on the live dvd that an actual install but.
I like pclinuxos because if I wanted to play dvd I can go to synaptic software installer and search for the library or lib I need that select it and install it. On other distributions they put you though loops meaning if I needed the same library I would need to add a repository to my system in order to download and install it. Which is not user friendly in my opinion.
Which version of linux you chose join the fourm. Plus PCLOS has its own cloud storage for free.
Last PCLOS is a rolling distribution meaning is is always updating and stable.
Here is your motherboard info this is ubuntu but an older version in this article.
https://wiki.debian.org/InstallingDebianOn/Asus/B85M-G