yannam - the comment you made - on the surface - evokes an initial reaction of, "Oh, that's a terrible thing to say." But the truth is that I could totally identify.
I think someone who has never been a parent of a child with a high IQ cannot relate, because it is easy to focus on the performance part of the equation and overlook the challenges. Being genius, profoundly gifted, or gifted is not some label that gives our kids magical powers to be superhuman; it is simply a complex mix-mash of unique skills ... and weaknesses. And so sometimes we almost sound ungrateful when we comment on the difficulties of parenting a high IQ child.
But the truth is that this tremendously uncomfortable experience can be a launching pad for a new area of growth. Shyness is a core trait and has its benefits (she doesn't need to be in the spotlight, is willing to "hunker down" and get the job done without being distracted, is good in one-on-one settings, etc.), but that doesn't mean that you can't begin to help her take steps in smaller, safer environments where she is challenged to reach out to others, interact with peers, and push herself to communicate. Work with her teacher to perhaps have her share a favorite toy or activity in circle time, get her involved in a community group in some activity that she likes ... little things that help her push herself slowly to build courage for facing larger audiences.
I recently had to give a presentation to over 600 people - all strangers, and I am an extrovert who found the experience daunting at best, but mostly just terrifying. So I cannot imagine how frightening it could be for a wee one to look out at that crowd where she is one of the youngest and not be able to get a peep out.
Hang in there. I won't say it gets easier, but it does get better. We as parents eventually come to the place where we embrace the funkiness of having an extraordinary child and celebrate their accomplishments that others may never understand, even when it is something as small as watching our child do something completely out of their comfort zone.