How would you feel??

Jessica • 29 years old, in love, and married. Mommy to Lucy born in March 2016. I am complete.
My sister has a daughter that was born last year. Their top two names were Brooke and Lucy. They went with Brooke. My husband and I love the name Lucy but I can't decide if it's off limits or not. I don't want to talk to her about it quite yet because we haven't announced gender.  Ps. Her husband says absolutely no other children so I don't think they'll be using it. 
Opinions please!!