Firstly, hope everything goes well

Now. It was kinda foolish to claim you were a convert, but thats history. Also, this girl that you think you can get on with; you need to tell her the truth. There's no point meeting up with her, and her mates, and then bluntly staying away from the fact that you're obviously not a Muslim.
If the relationship continues, and you continue to lie, mate you're in for a nasty shock. Girls don't take lies well, and you don't want to hurt a girl like that.
And please bruv, don't use girls for "somewhat intimate" relationships, or simply for sexual purposes. And if you plan to break up later, and simply use her, then please don't for the sake of the girl.
Come out clean.