What Breed Is My Dog?

We rescued Olive from the shelter with a Pit Bull label on her. But she has a lean body, she's about 55lbs, and a tiny waist with a broader chest. There's got to be some other things mixed in. We are curious if anyone with breed knowledge has any guesses. We'll eventually do a DNA test, but haven't splurged on one yet. I mean, we love her whatever she is, so it doesn't really matter, but she sure has us wondering!