Losing too fast?

You most definitely won't be losing 7 lb a week past the first week. Your weekly loss will likely be about 2-3 pounds a week from now on, which is actually quite fast compared to what lighter people are able to produce! There is such a thing as losing too fast though, and it's not all about nutrients. Preserving muscle mass is a pretty good thing to consider, which requires a higher calorie intake. In your case, however, you have the luxury of opting for a fast loss at first because your weight is kind of protective of muscle mass so you can handle a higher loss for now (but would need to increase your intake as you become lighter).

For the time being consider this: are you happy with your current intake? Do you feel constantly hungry? Does it feel hard? If you aren't reasonably comfortable on your current diet, you will likely not be able to stick to it. A slower consistent loss is better than a fast loss then rage quitting. If you are happy, you could stay the course for now, but re-evaluate later. You are in it for the long haul and will likely be dieting for a couple of years, so consider making yourself comfortable for the ride even if it means losing a bit slower.

Just follow what you are feeling. The body lets go of a lot of water retention for the first few weeks of starting a new diet and exercise program. Worry about the "too fast" thing after a few weeks of being able to compare.