I think it depends on how strongly you feel on this. How long did it take you to see her naked? If it took a while for you to "earn" such a privilige then you can use that as an arguement. Ultimately it is her choice, but I would imagine that if you are in a committed relationship then your opinion has to count for something
.
And as far as the statements to the effect of "I would not let my gf pose nude" I don't think the meaning is that the gf has to ask for permission, but rather that the person feels so strongly on the matter that if said gf posed against the wishes of her partner, that she would no longer be that persons gf.
I don't "let" my gf fuck other people, it is not that she has to ask my permission to do so, rather it is if she chooses to we are no longer together
.