Is it an electric? Investing in another guitar when you're just starting is kind of unreasonable, but if you're in the market for an acoustic and want something to really challenge you, get a classical guitar. Classical guitars are built with a wider, flatter fretboard than most guitars, which makes it quite a challenge to barre on. But, if you learn to play on a classical guitar, contemporary styles will seem like a breeze, because your hands will already be much more limber than you'll ever need to work their tiny necks.
Way to go on self-learning. I'm self-taught as well. The things that really helped me were to do lots of research, and to spend lots of time observing other players and discussing their technique. Another key part is to learn proper form early on - do a little reading on how to play classical-style guitar and you'll learn a lot of tips regarding the ergonomics of playing. Learning to hold the guitar right and keep your hands extended will save you a lot of discomfort in both the short and long run, which in turn will allow you to practice harder, play longer, and actually make use of the skills you're developing now throughout the rest of your life. (One of the saddest things I've ever come across was my buddy's dad, who played guitar his whole life up until the cartilage in his wrists and fingers wore away. He still builds guitars because he loves it so much, but the closest thing he's had to playing for the past ten or fifteen years has been teaching his son. He can still play beautifully, but not for much more than a minute or two at a time.)
A big part of teaching yourself is making it through the first stage, where you can't really play anything all the way through and you only know parts of a few songs. Keep focused and practice a lot like everyone's been saying. Make sure to find music that you can reasonably expect to learn, but that you also enjoy playing and will come back to even after you've mastered it. I'd recommend finding things in the genres of blues, classical, punk, classic rock, metal, or folk. Blues, punk and classic rock will teach you all about rhythm, chords, and progressions, and will help you develop the ability to play by ear. Classical, metal and folk music will help you learn about fingerpicking, composition, and musical theory, and most selections therein will be good practice for speed and agility.
If you want to be a real ladykiller, and impress all of the wannabe rocker kids, learn some Bob Dylan. And not just the chords - you've got to learn to play the melody with fingerpicking. There'll be plenty of folks who don't know his material, but if you can remember all the words to "Boots of Spanish Leather," you'll be a guitar god to just about anyone who isn't ready to start their own band.