I actively try to quite often take DD9 out of her comfort zone, and we talk about it as being a good thing. School is hopeless, but that's a whole nother story that we are working on
But I quite regularly find classes and courses on things that she's interested in and talk them into taking her (local homeschool groups and library activities are really good for this, and I take her to public lectures at universities). After some trial and error, found she should currently be working on 13-14 year old level in those topics to actually need to be paying and attention and making an effort and asking questions. And we talk about it in terms of how interesting it was, what was easy and what was challenging, what she learned, what else she'd like to learn in light of it, etc. Not how well she did or who she beat (I secretly tell DH these things!). Although, full disclosure, probably if she did struggle comprehending anything the sting would be taken out of it by being so much younger than anyone else. Also, I only work part time so it's not too difficult to find and take her to these things. So not perfect! But better than nothing
