I don't mean not encourage children to have friends over or anything like that.
But I have a niece who's 13 now and she's quite shy. At a party recently my SIL kept hissing at her to go and be sociable, 'look at all the other young people chatting together' etc and my niece just looked really uncomfortable and unhappy. She didn't really know any of the other kids apart from one who was her cousin, and obviously didn't want to go and hang around with them.
I have a friend who said her mother used to do this kind of thing, and tell her 'not to be so odd', or make a point of telling her about suchandsuch's daughter 'who's always at parties', 'they never see her she's out and about so much' etc and it just made her feel even more awkward and shy.
I know parents want to see their kids be happy and sociable, but if someone's just not naturally sociable AIBU to think you can't really force it. Kids need to find their own way, and not be pushed too much. My friend now has plenty of friends, and I'm sure my niece will find her feet in her own time.