Absolutely go for it. If you haven't already read the "Interested in Publication" entry, Brandon wrote a great response for the aspiring writer. We're in the same boat you and I. My first manuscript was finished back in 1999 and I've been seeking agents and publishers since. So far, no avail. Actually, with each new rejection, I learned there were problems in the story that needed fixing and I still have to make another revision of it. However, I finished 3 other projects along the way with no book deals as of yet, but that's not slowing me down. Though it is possible to have a first manuscript accepted and published, you ought not rely on a single work alone. Branch out. If you have more than one, try them all. I finally learned that a well rounded author is more attractive than one who sticks with the same genre and style, unless it's a series or something. What the editor has to say can be very helpful. So in short, throw in your fishing line. You might snag a whopper!