When you think of 'Nanny', you probably will always want them as female in middle age because they are surely more experienced for handling children.   But.  

Kai has always been a friend to you. Just a friend. Being the only person he's relying to, make you fall for him. His unpredictable character make you like him even more. What will it turn out in the end? Will he except you when he knows about it or will he push you away? Sinc