She'll know that u ordered it when she recives her bill to make payment on it. It will show her everything she took out or what she had bought. Kindda like a bank transaction. So just keep on eye out for her credit card bill. And u said she'd throw it out if she saw it if she don;t see it ur safe. And when she asks about where the money went if she finds out tell her u bought a gift for some party or what not.