Almost 1% of females in America are named Nora. That's about, what, 1.25 million? I'd say that's common enough. I know I've met a couple of people named Nora in my lifetime, if not more. And I'm only 26 years old. A friend of mine in intermediate school. It's a name more well known amongst the older generations than the young, admittedly - I often hear of Nora's in the elderly generation.
EDIT: To put it in perspective, there are more females in America named Nora than there are females named Claire (which even I'm pretty surprised at).
EDIT: Even Wikipedia details Nora as a common name. And the list of Nora's there isn't short.
EDIT: And the name means 'Honour' which is something which I think would be a reasonable name for her character. Perhaps they just wanted to name her something which means 'honourable'. This would make sense as she was an honourable character, putting her life on the line to defend her family with, well, honour.
