YA Fantasy trilogy 2 twin girls one with panther one with dog

I read the book probably 10 years ago in the USA, it was in English. I believe it was a series (trilogy maybe), and the main characters were two twin girls who at a young age were put in a room with a panther and a dog to see if they were the ones chosen to be whatever it was. If they survived then they got bonded to a baby panther and a puppy from their respective litters? Something like that. Then they went on a journey, etc. I forget the rest