Wendy - although I have never booked a Suite, I have been in one. They are quite large with a Queen sized bed and a sofa that sleeps 2, I believe. There is a dressing room, separate from the bathroom and a large balcony. They really are very nice.
Yes, the little extras are worth it if 4 of you are sharing. I know Suites get free laundry service, but don't know if applies to all 4 of you or only 2.
My husband, son, daughter (in their 20's) and I stayed in a much smaller room than the Suite on the Rotterdam V, years ago and it was fine. We only had a shower in the bathroom, but we made up a schedule of who would shower first, etc. and everything worked out perfectly.
You will be fine, I am sure.
Have a great time.