I've lost 91 pounds in about 25 weeks. I'm 5' 7.5", so taller, and I'm a Vegetarian. I also have walked almost all my life for fitness, so after the first 3-4 weeks on IP, I started that up, and have continued walking an hour or so a day. I also naturally have a good muscle base, which helps things along also.
I've had great and pretty consistent losses (but I have had the 1/2 pound weekly losses also), but that's me. Everybody has different losses at different rates for a number of reasons, so it's best to realize that. I never thought I'd lose this much weight this fast, but for some reason my body can do this (in the past, I've always been one to gain weight fast and lose weight fast).
You'll do great on this diet. My advice: just follow the plan, and let it do its magic, without worrying about how quickly you're losing weight. The longer you're on this diet, the longer you're eating tons of veggies a day, no sauces, lean meats, etc. And that's not a bad thing.

Good luck!