I thought that my child was sufficient enough to bathe on his own at about 6!! I figured that he could pick up his head if he put his head under water and understands the precautions that i told him before he took a bath! I did go and check on him though!
Your child should be able to bathe themselves by ten. They can start earlier with some supervision such as making sure they scrub their entire body and rinse their hair properly.
Every child is different so its most important to go by if you feel your child is ready to bathe on their own. Ask yourself will your child bathe properly and if so then he is ready to go at it alone.
Children should start bathing from the age 6. Because from that age they feel relax and free. They can change dress. They can whip with out their mothers help. And they also enjoy it.