A Nanny: Real or Fake

We have a new cleaning lady who came to clean the public areas in our apartment block. One morning, to strike up a conversation beyong the usual morning pleasantries, she said to me,
"Mummy is off to work early this morning so it is your turn to send the kids to schools.（今天妈妈早上班。你送孩子。）"

"yes" I replied.

"You dont go to work today(你今天不上班）?" she probed further.

"No, I am a full time nanny (我是全职保姆）"。

She stared at me for like 5 seconds. I thought she was going to throw me a question like 'You are joking!' or 'You dont look like a fulltime nanny', but not to be the case.

"How much（多少钱）?" she wanted to know.