My story was similar though not nearly as dramatic as your parents'.

I would suggest shifting your parenting focus away from school. If she's truly smart, she is going to be top of her class without any effort for at least another 6-8 years. So, what I would suggest is to first try and cultivate an ethic of going above and beyond, and always doing work you "can take pride in" (when the work is too easy, without established values it can get very hard to keep caring and avoid turning in B- after B-) and second turning her on to more outside of school. When I was a little kid this manifest as a voracious appetite for books and Legos, which fed my imagination and logical thinking. Magic (the card game) was my replacement for chess.

Different kids will be interested in different things, but in general they are hungry to learn, so if school is easy you just have to find that extra interest outside of school and they will go crazy. Science, especially life sciences, geology, and such are usually solid choices because a sharp child is going to be inquisitive about the world around them.

(Don't ignore school, of course)