I think it would be nice if this function would have some (customizable)
variables.
Here (in Germany) e.g. I like this:
(defun org-bbdb-anniversary-description (agenda-date anniv-date)
(let ((delta (- (calendar-absolute-from-gregorian anniv-date)
(calendar-absolute-from-gregorian agenda-date))))
(cond
((= delta 0) "\\&")
((= delta 1) " (morgen)\\&")
((< delta org-bbdb-general-anniversary-description-after)
(format " (in %d Tagen)\\&" delta))
((pcase-let ((`(,month ,day ,year) anniv-date))
(format " (am %d.%d.)\\&" day month)))
)
)
)
And I think others would have other preferences.
Just an idea.
I'm sorry but I can't program lisp good enough to implement my idea
(without the shown hack).