floppy

So I've had several pitbulls and have never had this problem. My blue girl is almost 7 months old and yesterday I noticed one of her ears is like limp. I got to looking at it and noticed a crease like spot kinda in the middle of her ear and it's like she doesn't have any control over the ear, as...

So Akasha has these wonderfully floppy triangle ears that I LOVE!! But I know that most dogs grow out of the floppy ears and acquire their Breed Specific ears (GSD stand up, APBT go all rose pricky so on.) Does anyone know about what age this will happen? She's 10 weeks 4 days right now.