In answer to your question of "how old old oldest?"... well... last month, I posted pics of my 30+ year old Dresden Plate, that I hope to finish this month. But, now that I think about it...
If I count a top that was pieced by my great-grandmother, and I put borders on... and that has been rolled up on my old hand-quilting frame... that one may well be older than I am. I really need to unquilt that and longarm it instead.