[2][3][1] In 1919, Shelly joined John Harvey Kellogg's Battle Creek School of Physical Education, graduating in spring 1922.

[3] Shelly attended the University of Oregon, starting to teach physical education there in 1924 and earning her bachelor's degree in 1926.

[5] While there, she, with fellow Kellogg graduates Martha Hill and Edith Ballweber, enrolled in Gertrude Colby's program in the physical education requirement.

The next summer, the Bennington School of Dance opened as an "immediate success",[7] with Shelly as the administrative director, dealing with "catastrophes" as they arose.

[4][5] Notably, the program hosted Martha Graham, Doris Humphrey, Charles Weidman, Hanya Holm, and Jóse Limón.

[3] In 1935, Shelly was appointed to associate professor of physical education and assistant to the dean of students at the University of Chicago.

While there, she became assistant to the dean of students and chaired the women's physical education department, directing the Ida Noyes Gymnasium.

[4] In 1939, Shelly helped Hill move the Bennington summer dance program to Mills College at Northeastern University under Rosalind Cassidy[4] and Aurelia Henry Reinhardt.

[4] In September 1942, Shelly temporarily left Bennington College to join the Women's Naval Reserve as a lieutenant in charge of physical training and drill.

She also faced low morale due to civilian women doing the same jobs, but in more attractive clothing and less restrictive positions.

In response to this, Shelly worked to make the WAF more elite, dropping quotas and raising the minimum Armed Forces Qualification Test score.