What a great cruise for a "first" cruise or anyone for that matter. Be sure to look through all the shore excursions and always a good idea to pre-book any that you really want, some do sell out quickly.
Which itinary are you going to be on. Also be sure to get tickets for the ice show, something you don't want to miss.
Each evening, read through the cruise compass to see things for the following day, times, places, etc....
Have a ball, I am sure you will.