My current helper is around 32 years old and takes up domestic helper job for the first time.
As you have said, they are more simple minded but you need to be VERY VERY patient in giving instructions and providing training in Chinese cooking. To us, GOOD ATTITUDE of a person always comes first. She's been staying with us for over six months now. We are quite happy with her performance.
I would advise you to let her know what are your priorities and give her a guide to follow. Ask her to consult you every time when she's in doubt. That will eliminate the possibility of misunderstanding.