Weird line, dent, leg fat??

My daughter is 18 months old, and I swear I've never noticed this until my husband pointed it out about an hour ago. This "thigh fat"? It's only on the one leg. Whether the knee is bent or not. We just want to make sure that's what it is. I know it's probably small and dumb but we worry 🤷🏻‍♀️