Here's stray thought (that may help to muddy the waters!). I try to learn several songs a year and, because I have a lifelong interest in traditional song, these are usually (surprise, surprise!) trad. songs. The thing is, although these songs may be a couple of hundred years old (at least), and may contain archaic turns of phrase, words etc. they rarely feel old and I always tend to refer to one of these songs as 'my new song'. Without attempting any further 'analysis' (ie. off-the-top-of-my-head, make-it-up-as-you-go-along waffle) there does seem to be a timeless quality about trad. song and the age of a song rarely seems to be of much relevance (oh no, not that word again!!)to anything.