yes. chinese is "in" nowadays everywhere. so, it is a good career for the times coming. about "au pair" there are some adresses in internet i suppose. if not ask for them in german consulate near you. i suggest München, in germany, Never been there, but it's a very dinamic city and not far from places interesting to visit. and good airport connetions.

In Australia, children learn Chinese in many schools, although others choose different languages.

If you go through an agency, be sure to ask for a few references from their current or former au pairs. That is, make sure that other au pairs have been happy with them. I don't want to alarm you, but there are a few dicey recruiters out there. Go with a reputable organization. Good Luck!