DD can do it all herself and has for quite a while, but TBH if she does a poo while she's at home I encourage her to call me and let me wipe (or at least check). I'm concerned she might not clean herself properly (sometimes she's really good, but others...). Reaching around the back is a bit harder. I'm more worried she'll give herself a UTI, since she's entirely responsible for her night time washing in the bath/shower.

All of her little preschool friends toilet themselves completely independently while at preschool, including wiping.