May I suggest, if we are to get to the bottom of this mystery, we might concentrate on trying to identify the students that will show us if SAD was in any classes AFTER 1958, because I haven't been able to find her. Other than the suspect 'no sweater' image which appears to have been created purely for the purpose of trying to convince us she graduated from that high school in 1960 - and an image with a weird hair style and a string pearls doesn't make a graduation...
You'll notice that Nancy Ramey has signed the back of one of the group images, (it's not possible to see front and back at the same time) and this image is captioned CLASS OF 1958. Tony Nugent also signed, and he was also Class of 1958.
WIKI SAYS: She graduated from the University of Washington in 1962 after spending junior year at the University of London's Bedford College. In 1967, she received a masters from the University of Wisconsin and later obtained her doctorate.