“Across the high schools studied, students with high school GPAs under 1.5 had around a 20% chance of graduating from college. For students with GPAs of 3.75 or higher, those chances rose to around 80%.”
That 20% of students with HS GPA < 1.5 graduate from college suggests that there is a non trivial number of “late bloomers”, and that one’s HS academic performance does not necessarily mean that one will continue to do similarly later.