Teaching good hygiene for girls

At what age do girls clean themselves adequately down there or grasp how to clean? Any advice for how to teach or explain how to wipe other than ‘front to back’. My daughter just turned 4 and she’s almost 100% potty trained but I still need to wipe her each time because if she doesn’t get cleaned good she’ll be crying at night with a red crotch then refuse to get in the bath or have it wiped (well it’s only happened three times). I know she’ll be doing preschool in the fall so she’ll have to learn before then.