There's nothing about her that would suggest she's using steroids. She's built like a powerlifter, very thick and muscular. Carrying more fat than your average BB, which is not a bad thing. Powerlifters want and go for higher fat percentages in comparison. That being said, she can certainly achieve that physique without steroids. Girls can become big and muscular naturally, what they cannot do is achieve leanness along with muscle density without some juice.
Also, if you've seen her brother you'd know she has genetics on her side as well.