What the other guys above said, it's better to have a few lessons to start out with when you're just starting out; it really helps get rid of bad habits and such. After around 3-4 lessons, you could stop (if you want) and start jamming with other musicians. I've learned that once you get your stuff together, jamming with other musicians is a great way to improve your playing.
After around a year of bass experience, take lessons again: your mind will be blown. Good bass teachers know what's best for their students and will know the best approach for you to make as a bassist to get to another level. They will teach you really awesome things if they get a good feel of how you play. Of course, only do this if you're willing to be open minded.
