Should you be worried if your teen aged daughter enjoys pooping in her panties?

No, you shouldn't be worried. It's something that she is into. I know you are a concerned parent. But let her have something for once in her life. If this makes her happy, or is something that she enjoys doing, then leave it at that. Just be supportive of her enjoying to poop her panties. Believe it or not, there is plenty of people her age and older who enjoy doing it. It's her choice, and her life, not yours. Like I said, just be supportive. As long as she is willing to clean up after herself and do her dirty laundry, there is not one thing wrong with it. Nobody needs to know about what she is into but her. Trust me, this is for the best that you let her have this.