We are mid-late 50's and have previously cruised both RCCL and Princess.
We had a great time on this cruise.
If anyone has previously only cruised in the Caribbean, it is good to be aware that cruises to Alaska are different than Caribbean cruises, no matter what line or ship you are on. The fellow passengers will tend to be slightly older and there are not the pool side festivities that Caribbean cruises are well known for. Alaska is about the scenery and wildlife.
We had E201. We liked our cabin. Downside is that it is way front and a long walk to anything including the stairs or elevator. I also didn't like that the window was high above the bed. The window was not conveniently located to just sit and look out the window. On the plus side it was quiet. I was worried that I would hear the noise from the theater below. On a couple of nights I heard a very faint sound of music, but very faint and my husband didn't hear it at all. It was not disruptive to sleeping. I would not hesitate again to book this cabin except for the long walk to the elevators and stairs.