Hi and welcome
A few things:
1. Weight loss is mostly about diet: eating fewer calories than your body uses each day. Any exercise or activity will help create a caloric deficit- running, walking, biking, etc. But it's easy to cancel out this deficit if the diet part isn't managed- eating fewer calories than your body needs.
2. Eating healthy often isn't enough- it's about eating less. Are you calorie counting or using an exchange program, or any other method to manage portion size?
3. Weight will sometimes stall after starting a new exercise regimen. This is due to the muscles retaining water. Dropping sizes is a great indicator that your body is continuing to lose genuine weight even if that may be masked by increased water. The body "calms down" a bit and releases water after a while, so give it two or three weeks after you've started a new exercise before you take the scale seriously.
4. Even without changes in diet or exercise, weight loss is not linear. You can stall or even see your weight bounce around at any time. This is not a bad thing, just a fact of weight loss.
Congrats on your great weight loss so far, and your commitment to exercise! Best of luck
