You and I are fairly close in age and height (although not weight, fortunately for you!
). I've been zig-zagging my calories and sticking to an average of 1500 calories per day, averaged weekly. For exercise, the minimum I do is half an hour of walking daily, though most days I also add in time on my stationary bike or free weights.
1200 seems low to me, too, but other people swear by it and are satisfied with what they eat at that number. More power to 'em! For me, though, 1500 calories is working great. So far, I've stayed completely on plan since I started (Oct. 19), have never gone hungry, and haven't felt deprived. I've lost eight pounds so far, which is a pretty fast clip given how easy my plan has been on me.
ElizabethG's suggestion to track normal days is a great one. Just getting in the habit of weighing and measuring is useful, and having a baseline at which your body's at equilibrium tells you a lot about how much you'll want to pare down to start losing.