I think you'll be happy once the time comes for your cruise. For future reference, most good prices for cruises are 6 - 9 months from the time you are looking to sail. Example, January for a September sailing.
I think a 5 night cruise is perfect for a first cruise to see if you enjoy it.
Whether you book through a travel agent or through the cruise line, the prices are the same. The only difference is if you book through the cruise line, the cruise line pockets the commission they would have paid the travel agent.
2007 - Majesty of the Seas (Bahamas)
2009 - Enchantment of the Seas (Western Caribbean)
2010 - Freedom of the Seas (Western Caribbean)
2013 - Golden Princess (Alaska, roundtrip from Seattle)