Me: fifty-something single woman, somewhat experienced cruiser, on my first solo cruise. I enjoyed the Norwegian Sky as a good weekend-getaway ship. The Sky, with its short itineraries and open bars, has a reputation as a "party boat," and I did find the average cruiser to be a bit younger (and drunker.) But don't be envisioning an out-of-control frat party or anything remotely like that... it was still perfectly family-friendly (indeed, there were many young families with toddlers.)
My balcony cabin seemed small, but since I wasn't sharing, it was plenty for me for three nights. The decor is a little dated-looking, with that bleached-wood cabinetry that was popular in the nineties, but all the light-and-bright fabrics of the bed linens, curtains, and so forth made the cabin look open & cheery. I found everything to be in perfect working order. Only complaint: the shower was almost too small to turn around in.
Meals in the two main dining rooms were uniformly good. (I didn't do any specialty dining.) The food was quite fresh and well-prepared, and there was enough variety on the menu to appeal to a wide range of tastes. I particularly enjoyed the seafood entrees. I only used the buffet for breakfast, but enjoyed the standard breakfast fare... sausage & eggs, a selection of croissants & pastries. There was plenty of seating in the buffet area, too, so it wasn't hard to find a table when I was ready to sit down.
Cabin was smaller than I expected, but neatly kept. Couch was stained but otherwise clean. Looks a little dated, but cheerful. Unpleasant smell of food cooking was sometimes pretty noticeable from the balcony. Also, I smelled cigar smoke from the balcony several times, but I don't know if that was from the cigar lounge or if someone was having an illegal smoke from his own balcony.