I'm sure my mum wasn't still wiping mine when I was 6.5. Getting very fed up of having to run upstairs to wipe her bum.
I've tried telling her to have a try herself and I'll inspect. This worked for a day and then she gave up. I probably need to stand my ground more and refuse to do it but she goes into meltdown and anything for a quiet life I cave in. I've explained to her over and over again what needs to be done. Have done it with my hand over hers. There's no earthly reason why she can't do it but she won't.
She doesn't poo at school if she can help it, comes running in desperate for a poo. If she does go at schoo lshe comes back with a sore bum and mucky knickers. Arghhhhhhhh.