Not wanting to get flamed! but here goes.
Time and time again on here its stated those who transition do so in the knowledge that they could lose everything in their life, friends, family, job but still they transition because they have no other option. I was lucky, most of my friends remained, my partner a heterosexual woman is now my best friend (she has another man in her life), and my employer has strong gender policies. I was prepared to lose those friends/partner, it may have been more difficult without a job though!
I see these threads and the phrase "wanting my cake and eating it" springs to mind - I'm sorry but "girl with a penis?" No - as Reine says, girls don't have that appendage. In my opinion, MTF TS's don't get the privilege of calling themselves women or girls until they start living (and I mean living, not just putting on a dress to go shopping etc) in that gender, by all means consider themselves non-op MTF TS but calling themselves women or girls while still living as a man, no sorry, doesn't work for me.