Nostalgia, by definition, is "a wistful or excessively sentimental yearning for return to, or of, some past period or irrecoverable condition."
Ptooie on the dictionary - excessively, indeed! Nothing wrong with nostalgia.
It's one of those things that is whatever you think it is. Whatever you feel nostalgic about is what it is to you. It can be a star-crossed love affair of last year, or years ago, or the events of a time before you even lived that impress themselves on you. If you like reading about the days of Camelot (the original, not the Kennedy Administration - or that, too, if you like), then that's nostalgia to you.
Why not? Should we try it out?
'Slipping the surly bonds of earth, to dance the skies on laughter-silvered wings'