Absolutely! A Travel Agent is just that, an Agent working on your behalf. They have access to the same deals and pricing that the cruise line offers directly. It does not cost any more to use one. They are often more knowledgeable about the Ships and Itineraries than the order takers with the cruise line. It always amazes me when I ask which ships the reservation taker at the cruise line has been on, and the answer is none.
One of my favorite quotes is ...
"A Travel Agent is an experienced traveler, a knowledgeable guide, an invaluable resource, a fulfiller of dreams."