I've got some general thoughts knocking around in my head, not in any particular order.
First: strengthening young women's desires to serve full-time missions is a good thing. In our ward, our bishop and ward leadership have put a lot of energy and resources behind that. The bishop has made sure to call at least some YW leaders who themselves are returned missionaries. We have a strong tradition in our ward of sending sister missionaries. At the moment our family is getting emails from three sister missionaries we know who are currently serving and we try to share those at the dinner table and talk about it with our kids. Draw on the resources in your ward of returned or currently serving sister missionaries to talk about preparing, teaching, and missionary work - it's a good example for your young women.