15 pounds in a month and 3 days?

Your initial weight loss is quick and then it will slow down. Particularly if you are overcoming really bad eating and exercise habits. Rejoice at your initial success and let more come. Eventually it slows to about 1.5 pounds a week, or thereabouts.

Make the most of it while it lasts. It will slow down considerably.

I lost 15 pounds in about a month and 3 days... is that normal? should I be worried?

Are you finding what your doing easy (do you feel you are getting enough food)? It is normal to lose a lot of weight on large calorie restrictions. If it's healthy to be on large calorie restrictions is argued. The larger you are the easier it is to lose quickly though. What amount do you have set to lose a week? Do you log and eat back your exercise calories? Since you're female if you are much below 2000 calories, my only worry would be nutrition and a slower pace tends to let the body/skin adjust easier.

That's a great initial weight loss. Since you say you don't eat back your workout calories and you get plenty of food, then that's great but don't get discouraged when the loss isn't as quick. It will slow down but keep doing what you're doing!

I lost 15 pounds in 6 days a few weeks ago. So..... Sure.

The first bit always falls off faster. I lost 15lbs in just over 3 weeks...but it's already starting to slow down drastically. Just try not to get discouraged when the weight loss slows down! The closer you get to your goal the slower you will lose!

Good luck!!

I lost 15 pounds in 6 days a few weeks ago. So..... Sure.

Wow, how did you do that?

I think it's ok I had lost that much in my first 3 weeks of my weight loss journey and my personal trainer told me it is normal.