It sounds like you have really done your homework. Either Golden Princess or Norwegian Pearl will give you a wonderful experience.
Someone said on this site that if you want to know if a particular ship or cruiseline would be a good fit, look at their advertising and ask yourself, "do I/we look like the people in those ads?" At 28 and 24 I think you will find Norwegian Pearl to be a better fit. My personal choice would be Princess; but then I'm 67 :-)