Ooh wwt, not long to go now! We're doing the same with our little one, DH speaks English, I speak German. She's only two months so obviously I don't know yet how well it's working.
It's harder than I thought though, as I tend to slip into English when there are other English speakers around. I'm working on it though and am hoping to get myself sorted before I confuse her too much.
Mummies who are speaking a secondary language (not the one native to your location): Do you have contacts who share your language locally, like an expat playgroup or something? I'm lucky in that my sister lives close but am still looking to meet some other German speaking mums and babies around here.