Dd's 10, been to lots of sleepovers but always with the same group of kids she's known since Reception class. She's got new friends now, and the mums seem nice but I've only spoken to them for 2 minutes when dropping off /picking up . Now she's invited to stay over and it doesn't feel right for her to be overnight with a family, other kids/dad I've never met. Am I a boring old misery or right to be cautious about it?