Straight girls: it all depends on the girl. Some/many girls will immediately consider you a girl or "not REALLY a guy" as soon as they find out you were born female/don't have a penis. Some girls (often those with bi/lesbian backgrounds) won't give it a second thought - or if they do, they d*** well won't tell you about it. Many girls who have been straight all their lives and initially thought you were bio-male would be uncomfortable with it at first but may gradually grow to accept the idea (although her plans of marriage and a family might shift to a well-just-for-now-until-I-look-to-settle-down plan). The key words in this third type are "initially thought you were male", which your girl does not fit into.
In all likelyhood? She probably views you as a girl because that is how she met you and that is how you appear at the moment (a girl's voice, boobs, feminine face, and short stature soundly douses the weak spark of a voice crying "I'm really a guy!" in the minds of most). Initial perceptions (especially those validated by what she sees/hears subconsciously) are difficult to shake off. But then again, she may be one of those special ones who could handle being with a transman and not having an identity crisis about it. Like I said, it all depends on the girl.
