absolutely you should have an agent! First of all, any publisher worth publishing your work will not look at your work (aside via slush pile which is like trying to win a drawing against a horde of other writers) unless you are represented by an agent. Second, they (agents) will have insights into the business that you don't and editing assistance that you may have overlooked. A friend of mine went through 250 queries before he found an agent. Now he has a 3 book deal with a six digit advance. I'm not saying that if you get an agent you'll get an advance like that, but the chances of you getting published and receiving the deal of a lifetime go way up with an agent. Besides, if you land one and you don't like their performance, fire them and find another. With a proper query letter and a story that grabs their attention, you can get an agent. Please, oh please, don't receive a dozen rejection letters and give up. Rejection is a part of the game and only the persistent, with a little luck thrown in, get published with a worthy deal. Good luck, and we'll be seeing you on the other side of the rainbow.