Her writeup when receiving the National Medal of Science in 1998: http://www.ams.org/notices/199903/comm-morawetz.pdf
The current US president is 71 and on average women have longer life expectancies so it doesn't seem that high an age to be leading a group like the AMS.
When it comes to Pure Mathematics, isn't that true in general?
Reqiescat in pace.
With that said, who is Cathleen Morawetz? And why should I, a random software engineer at Google, care?