My 5 yo twins try, but they don’t do a very good job and they know that so they usually ask for help, which I don’t have a problem with. I do think I’d have a problem if they wouldn’t wipe at all, but that’s a parent’s job, not yours. You can encourage her to wipe, but don’t push it if they don’t. Maybe they have their reasons (like she doesn’t do a good job, or she wastes TP)