The incredible shrinking waistline, is this normal?

So I started strength training a week ago, about 3-4 times a week. I was very concerned because my weight has slowly been increasing on the scale but today I measured me waistline and its down about an inch and a half. Is this normal, and should I continue to strength train or should I kinda stick to dieting and doing crunches. I have a pretty good diet: I'm vegetarian, no eating after 8:30 veggies and fruits most of the day and only snack food at dinner. I also have a protein drink for lunch with salad and veggies.

Any help would be greatly appreciated, thanks!