i think that more than age is the attitude. Is she active not o ly running and playing but also reading and talking and singing? Does she come on time? Can she cook a meal? Stay late if she's needed to. Does she have a positive attitude ? Does she likes the library and the park? Does she keep the children safe? Does she spend a lot of time on the phone? Thera are so many things to describe a good nanny and it's not only the age it's more than that