A GED opens the door to further education and job placement; the SAT doesn’t. Otherwise, when I took the SAT (also at 12), I would have jumped into the job market then and there! lol
That's screwy. The GED is less than high school equivalency. There is absolutely zero rigor to it. It might get you a job as a janitor. It certainly doesn't get you into any reputable college or university, although some community colleges may except it and then a person can prove their academic worth.
The SAT and ACT get you into college. A GED is only useful when you home school and your school district will not give a diploma, or if you drop out of school. It means nothing academically. Both of my daughters home schooled and did not receive a high school diploma. Their SATs in combination of a portfolio of home schooling work, and multiple AP Exams opened the door to colleges/universities.
Also, the idea of jumping into the job market as a career choice at age 12 is hideous, or age 16 for that matter. There is nothing wrong with working at those ages, but there's a lot of learning to do to avoid ignorance as an adult.