I was one of those "gifted left behind" students. Majority of my family never completed high school and no one in my family went to college. High school was the bare minimum requirement to work at the local furniture factory and that is where you were expected to work after graduation (college was out of scope us simple folks).
My high school barely offered any AP courses, didn't prepare students for the SAT (I didn't know what it was) and despite having nearly a 4.0 GPA (unweighted, since I never took any AP courses) the "best" college I was told I could attend was a local nearby liberal arts school. I had no guidance on where to go to college nor any preparation.
I showed talent at an early age but there were simply no resources for me. I ended up going to a community college, had nearly a 4.0 GPA (taking mostly STEM courses) and a guidance consoler recommended I apply for a prestigious university located in the state. I told her I couldn't do that as I knew I wouldn't be accepted, told her the acceptance rate is too low. She tried to push really hard for me apply and said I would get in. I declined. Instead I went to a much lower ranked university (looking back on it I could have gotten into the initial school) and ended up doing research there. The research led to a publication but for one reason or another my GPA dropped and continue to drop each semester (had A+s, As in some courses, Ds in others). I received help from no one and had no support system.
Ended up transferring to a larger school. Started over there, GPA continued to suffer (was dealing with a lot) and graduated. Despite my low GPA I was accepted to a highly ranked graduate school and was offered a fellowship, teaching assistant ship and research assistantship, but I also received a job offer with a much higher starting salary. My family was in such need at this time I had to accept the job over graduate school.
After working in industry I developed a new interest and decided I wanted to go back into academia. At this moment in my life I'm preparing to make the switch. I enrolled in a well-ranked university taking pre-req courses in the new field and currently pulling off a 4.0 GPA. I plan to apply to graduate school shortly.
Most of my friends had more of a straight path into graduate school.