Scotland To Sweden Long distance relationship?

I've been talking to this girl over the internet for the most of my teenage life. I'm 17, as she is. I'm in Scotland, she's in Sweden. We both live at home with our parents, and I really want to go see her as she really wants to meet me. After I've got the money, I want to ask my parents, but I don't know how to go about asking them, they will ask how do I know who she is? When I've seen her in camera, I know her dad, I've spoken to him and he said it'd be great if i could come and stay with them for a while (1 week or 2) I just have no clue how to ask my mum about all this, because she always jumps to conclusions before knowning the facts. Can anyone help me?