It will be fun. I just completed my 38th cruise, and number 39 is coming up next month....first trans Atlantic voyage. I concur with the advice already given on Cruise Critic.
I have both booked direct and utilized the services of a travel agent. Depending on the number of cabins you book, you may find benefit in coordinating a "group cruise." I did one for my 40th birthday...there were 23 of us. I hosted a cocktail party on board, and each cabin got a $50 credit as a group benefit. I know Royal Caribbean requires you to work through a travel agent if you are cruising as a group which they define as 8 or more cabins. That could vary by cruise line.
I wrote down a few primers on
cruising for beginners here. Please know that FT rules require that I alert you that the blog that follows that link is one where I am a contributor.