Some posters sound almost as if they are in competition with their children - "I did this, so you should do at least as well".
I remember my Dad saying once, when I got 94% in Latin and came second in class, "good, better, best, never let it rest". This reminds me of the "B is a fail" comment. Luckily my mother had the frying pan to hand...
To me, that is not motivational.
DD1 has recently taken up riding again, and I was thinking about doing it too. But, for various dull reasons, I would need to be in the same lesson as her - and I'm naturally a much better rider than her (more empathy, taught better as a youngster, years more experience blah blah). So I'm not going to do it - why would I try and steal her experience?
One of my DDs is below average, the other just above - I encourage and support, provide help if it is required, provide opportunities they want (eg riding, music, maths tutoring at primary) but the crucial thing is it is their choice, and they can stop doing it without any kind of comeback.
We are creating individuals, not pegs in a system, as long as they can think for themselves and discuss the issues/route they need to take to do something, then I think you have to trust them to develop.