I think that the fact that one of your children was naturally shy is the real issue. Shy people tend to have difficulties that non-shy people don't have. I could be wrong of course, but that's what I believe, as a shy person who on account of my birthday started school about a later than average. I also have siblings who are utterly different to me and who are high achievers etc.

I think its more nuanced than that. I am very shy, but I think have done okay largely through being ambitious, which cut through shyness at key times. A lot of people I work with are the same story I think

True, there are lots of factors at play. All things being equal though I believe shyness is a hindrance to being successful both socially and professionally in the conventional sense.

As a shy introvert myself whose even been suicidal in years past, I'm thoroughly aware of the obstacles it presents. However, since becoming a personality researcher, my views have shifted to viewing it more as a net positive for a lot of things, and it's certainly less of an uncommon opinion these days:

https://youtu.be/85s9wJlzkrk

That being said, there are a variety of other character traits that play a role in how different people reach success, thus part of the issue is simply the interpretation of "success" itself, because quite often we look to very specific examples of successful people (e.g. Steve Jobs) or paths, that don't suit our personality taits nor strengths at all, and set us up with unrealistic expectations for ourselves.

Success comes in all forms, shapes, and sizes, so there should be no reason to let certain traits limit us on the hunt for success, when the game is largely about filtering out the noise and focusing on paths and pursuits that actually play to our strengths, instead of ones that make us perpetually anxious and stressed out.

Also shy but I realised fairly early on (early 20's) that you can't be entirely shy and function in a society with people that mostly aren't so I cultivated the ability to overcome it for nescessary tasks but honestly most of the time I'm happier in my own company with a book than out with my friends.

I hear a saying a while back and I'm murdering it but "Introverts recharge by themselves and extroverts recharge with other people" and that is me, in small stints I can be gregarious and outgoing but within a short period I just want to be on my own again, I find it tiring.

Thank you for sharing your story. Last year, I and my wife deliberately decided to minimize applications to schools with my kid who seems to have similar social/academic tendency as your first one. We applied one school where such kids could also be thriving, and ended up not getting accepted. She would need to go to a school this year, and within a year, my kid became much more mature than a year before, and we & people around her think the delay was probably good for her. Just wanted to add my anecdote.

"but is not doing so great as an adult"-- what do you mean by that?

I was sent to school early. I handled it well intellectually but, I was physically smaller than my classmates. That made school difficult at times.

Same. Weird stuff also bothered me like not being able to drive when everyone else could or not being able to drink when everyone is going to the bars. You're not even allowed in sometimes.