Congrats on your loss! I also had a great first week (14 pounds the first week), but the losses slow down quick (I lost 6 pounds the second week, for a total 20 down in 2 weeks). After the first 2 weeks, I hope to settle in for an average of about 2-5 pounds a week; then it's a matter hanging in there and staying consistent.
That might seem like a lot, but I am losing at this rate because I also weight train (hard core) with a trainer 3x a week, along with an hour of cardio every day. I eat somewhere between 1200-1600 calories a day to give me the energy and protein I need for those workouts. I am very muscular for my frame; even at my highest weight (325) I had a body fat percentage of 34%. Most women my age, height and weight are usually much higher (55%+). That means I can burn fat pretty quickly, as long as I don't out-eat my metabolism--which unfortunately I'm very good at doing.
Congrats again on your initial weight loss; just think, even at 1 pound a week, that's 52 pounds in a year, and that's a lot!