Good story, and i agree with Tg it's interesting to pull it all off in first person, though it also results in overuse of "I" and a feeling that we know she will always have her way.
The basic setup seems rather strained to me - no pro BDSM Domme or erotic model uses her own legal name in her work (and so her parents wouldn't find her by simply clicking on google) and i really don't get it why her dad would surrender like a boy to his daughter just because she enters in a Domme costume. The idea that he'd have dreamt of being Dominated by his own little girl feels really far out - her mother calling her Mistress Susan and accepting to be called "slave Mommy" even more so! - but if some readers will like it then okay.
I'd have wished for the story to be more sensuous and suggestive too. This shouldn't be seen as an indictment, but it's not really my kind of story and I think it needs a counter-player who is able to balance Susan.