Yes, it certainly is not, but these scams can come from anywhere, like those emails where someone in Africa has inherited millions but needs to use your bank account to get the money so they need your account info. Scams are everywhere. If this person really wants to marry you she will be willing to come to the us as a visitor or accept you coming there as a visitor before she asks for money. I would be kind of suspicious if she makes up reasons why neither of these situations can happen before the wedding has to be paid for.