Honking = duck. I don't think you need to wait unless what your new duck is doing is peeping and not honking/quacking. But, since you said "honking" I'm going to assume there's no confusion that it's a girl.
If it quacks like a duck, it's a duck. If she's only a few months old I wouldn't be worried about her being smaller than your previous duck.
Your male has a raspy, frog like voice right?
I've never known standing in the water and flapping to be a gender specific behavior.