The good news is that being selective in social situations isn't really a flaw to fix - plenty of confident adults prefer smaller gatherings too. That said, if your kid wants to feel more comfortable in groups, start small: maybe invite one classmate over repeatedly so they get comfortable, then gradually expand to small group hangouts where the environment feels safer. Let them pick activities they actually enjoy (gaming session, movie night) rather than forcing awkward socializing, and resist the urge to jump in and rescue them from quiet moments - sometimes just sitting through the discomfort teaches them it won't kill them. Books on social anxiety can help them understand what's happening in their head, and honestly, just knowing their parent doesn't think something's "wrong" with them goes a long way.