Just for comparison, I know of kids who passed Novice and Technician Amateur Radio Operator exams at age 5. It's a big enough accomplishment to warrant a news
story on a TV station. That requires some reading and math literacy to pass the exam. That puts these 5 year old kids well beyond what passes for a "high school graduate" in Baltimore. That's not even sufficient to work at a minimum wage fast food job or stocking shelves at Walmart.
I once saw a test that required passing to graduate 8th grade back at the turn from 19th to 20th centuries. I consider myself pretty well read and well educated, but I wondered at the time, whether a college grad of today could pass it.