Roxy and Zoe are failrly common names, so if you are at a dog park don't be suprised if three dogs run up if you call either name, and since yours is a boxer, she will still be out running around!
Just picture youself somewhere yelling a name. Whatever name seems most naturla to you is the ine you should use. Trust me you will use more than youever thought you could! Especially around the the troubling teen stage around 7 months.
I love this breed with all my heart, but they can be a stubborn lot!