17 :) ...
16 - 20 from college
I was homeschooled and never went to a highschool, but I completed 12th grade when I was 16.
16, finished my first degree at 20, my second at 24, my third at 27
18. Back in the day a young man had to register for the draft by his 18th birthday. Among the cards I received after high school graduation was my 1-A classification from Selective Service. 1-A meant you would be in uniform soon.
Left home and HS at 16, joined Navy 17, tested and received a GED, adult education received HS diploma 21, Junior College 22-23, University 24-25, and then earned a graduate degree, an MA in Psychology at 27.
19 I was on the Lifetime Program.