Definatly take lessons if you can. I can't stress enough how important it is to develop good habits and stop bad ones. I used to have tons of badhabits, which at the time, I thought were quite benign. But when I started taking lessons with an incredibly gifted musician, he corrected me (it's a hard process to go back and change bad habits, believe me), and now I'm progressing fabulously. A good teacher can not only teach you the right way to do things, but can also inspire you and widen your musical horizon.