Not sure how close you all are, but maybe you will feel differently depending on how it's "delivered." I know my sisters and I have received and have even given each other the same gifts. I think it can be presented as a nice gesture that you share a bond and are meaningful in each other's lives.
You could also buy a different Alex and Ani bracelet so there's a similarity of item, but not the same exact design. In the case of my sisters, we like different metals. So it's not exactly the same.
Whatever you decide. It's a gift and I'm sure the thought is there. You could include a nice hand written card to express your sentiment as well. Good luck!