I just need some advice on upgrading from 12.10 to 13.04.
What happens when I upgrade? Do my files, settings, and internet bookmarks stay intact? I can't find any resources to help me with this.
Upgrade means: it will update the core software to new features and better functionality and by doing this update you will never lose any of your personal data, files or installed applications.
Upgrade simply means shifting your home from a Single bed room flat to a Double bed room flat. All your stuff will be there and there is room for some other more but its risky too for arrangement in the new flat.
So There is a chance that you upgrade can fail and it will take the stability of your system or it may be dont want to boot after upgrade , WiFi , VGA drivers , etc many issues are there .
If I were you , What I do ?
hope that helps.
Still it is advised to clean install the new Ubuntu. If you have a /home directory then in my recommendation you should format old Ubuntu and install new one. If you don't have /home then it's alright to upgrade in the formal way. (I answered just based on my knowledge. I myself never upgraded to new Ubuntus).
You can't upgrade from 12.04 to 13.04. You need to 12.04 -> 12.10 -> 13.04. But 13.04 support stops in January 2014 so you better upgrade until 13.10 which has support until April.
Your system files get upgraded. Anything that it's not
Just a piece of advice
Since you will be downloading 1.5 years worth of upgrades, the easier solution is reinstalling Ubuntu 13.10 or waiting until April when 14.04 LTS gets releases. Many successive upgrades tend to break things around and also your bandwidth will suffer.