Same name both wanted by family

My SIL and I are both pregnant at the same time, she's due 4 weeks before me. When we found out we were pregnant we automatically knew the names of it was a boy or girl but chose not to tell anybody (to avoid any unwanted comments/advice). Well now my SIL just announced that they chose the same name we did. Urghhhh. My initial reaction was "Hey that's our name" but scared it'll cause a dispute. Crap, never thought this would happen :(