Thats not entirely true, you always have to make sure your guitar can handle the string guage you want to put on...and its a good idea to have your guitar set up when changing guages.

You have an Epi Zakk Wylde right? so you dont really have a problem with tremo, and springs, so guage differences arent as important for you, as say, for someone with a floating trem equipped guitar.

that said, why will you be getting a new axe soon? the Zakk Wylde sig is a nice guitar, and as a beginner, you wont be out growing it for a while still...hell, you may never out grow that axe, (but that wont stop you getting more guitars)

my suggestion, (since you got the guitar so cheap, I presume you bought second hand? or off ebay or summin) is that you take it into your local dealer, and have them set it up, and replace the strings with a guage you are happy with...not only do you get new strings, but a well set-up guitar is so much more comfortable to play...a bad set up can ruin even an incredible guitar.