The youngest college graduate was 10 years old.

Michael Kearney was the youngest college graduate, receiving a bachelor's
degree in anthropology from the University of South Alabama at the age of
10 in 1994. This achievement led to Kearney being entered into the Guinness
Book of World Records. Diagnosed with Attention Deficit Hyperactivity
Disorder (ADHD) at a young age, Kearney's parents refused to give the child
the prescription Ritalin which is usually given to those diagnosed with the
disorder. His parents chose to home school Kearney, and he was able to
graduate high school when he was 6 years old. Kearney continued his college
education, and at the age of 14 received his master's degree in
biochemistry from Middle Tennessee State University.