Buckle up it's a learning curve !
I bought a thinkpad laptop cheap just to learn how to use linux on, tried ubuntu on a dual boot on my pc, that was enough to convince me to learn how to use it 'properly' - don't dual boot would be my recommendation, put it solely on a machine to learn from if you can.
be prepared to learn and make mistakes, it's not windows (thankfully) bit it'll take some time to 'get' it. first install, wipe the disc clean and do a bog standard install, then if you want to partition, do it all again and read the pdf guide at the top of the forum, it makes sense and it's a good guide for newbies, and after 9 months or so on linux i very much consider myself to be one lol -
i've tried about 6 different distributions and just come back to mint from ubuntu 10.04, which was excellent, but there's just something about mint that brings me back . . . . . if you're pretty good with formatting/installing windows that will help, a bit, but not completely, everything's got different names and terminology which won't make any sense at all at first but that's what the forum's for and there is no shortage of help, just remember it make take a short while for answers as people are in different time zones etc. google is a pretty good engine for answers, use it, you'll be surprised how quickly you'll find your own answers.
if you have the time and patience and want
to learn, you'll be fine, and you'll like it, it's a fantastic OS and once i'm confident enough with it I won't ever be buying a windows license again . . . . . . . .
Most of all . . . . . have fun