I have Ancona's and I would guess she's a hen. The tail curl or "drake butt" feather is not present, but if a molt was recent it might not be back in yet, Ham-n-Cheese's always takes a couple months after a molt to come back in. The head looks more like a hen to me, boys have a kind of blockier head and are a bit bigger than hens. Hens have a more graceful curve to their head. The only way to know for sure is to check manually or wait for eggs. Congrats! I really love my Ancona ducks they are super funny and pretty mellow. Enjoy her, and I am with Goatwalker on the get her some more ducky friends, ducks are the best, very messy, but totally wonderful.  
Goatwalker, we are gonna talk soon. Hows your bator working? I am thinking about trying to ship some fertile eggs for testing, and you are first on my list.