Not wanting to waste any more time, I also went to Flickr and found this lady. (There was an interesting story attached.) Her face was actually wider, her head at more of an angle and her expression more 'knowing' but I've run out of time.
This lady does not have that many lines so doing the drawing made me focus on the identifiers that make a person look 'old': grey hair, lines, loose skin, large ears, liver spots, a bent frame and, oftentimes, a wise expression. (Gry mentioned some others in her post.)
(Medium Derwent Onyx on A6 copy paper.)