I got my GED when I was 14, at the end of 9th grade. I didn't know it at the time, or I didn't think it all the way through but I could have gone directly to college from 9th grade. I could have gone to community college and had an Associate's degree by the time I was 17 (which is what I have now and I'm 47).
The reason I stayed in high school was
1. I thought a diploma was better than a GED. But I was wrong. A GED literally means you know enough to go to college. You can get into any college with a GED. Especially if you're 14.
2. I wanted to do high school stuff like go out on dates, play on the basketball team, go to the prom, etc.
A person with a GED isn't a high school dropout. A person with a GED finished high school.