I would love to know what changes in color peonies go through as the seasons change.
I'm not sure if this peony is the type that changes color easily. It might start out a vibrant shade of red and then, as it ages, the color might gently fade and become a bit more muted.
If I'm not mistaken, the Karl Rosenfield Peony plant is famous for its deep, vibrant red blooms.
I'm not very familiar with Karl Rosenfield peonies, but I know that they generally don't undergo major color changes.
Don't worry about the plant's color changing much at all. As it gets even older, its flowers might get a touch darker, but that'll still be a beautiful, natural change, not something you need to stress over.