You are doing great:-))) Congratulations to your remarkable weight loss.

It is very common not to loose weight (sometimes even to gain a little) during the first weeks of a new exercise routine. Very simply your body reacts with retaining water to the higher/new demand. But it does not mean your body does not change - you already noticed thinning areas.
How long it takes to see weight loss again? For most of the people who start exercise, it takes 4-6 weeks. Be patient:-)) And the most important, hide your scale. It can be very frustrating to see the exercise related WATER weight fluctuation.

Believe me, I know about frustration. I lost 35 lbs, without seeing even ONE inch lost from my waist line for 7 months:-)

Cheers:
Eva