She seems to have been in the “high school department” as they sometimes called it. From the late 1860s to the late 1970s, we had a campus school. It was an actual school, with children from the village, for our student teachers to learn, to try out new educational ideas etc. The grade range varied over the years, but for a long time the only high school in the village was part of our training school. The village didn’t have it’s own high school until around 1930.
So your grandmother’s ring is a high school class ring, from when the high school was housed in the Normal school.