It's a difficult age. Everything depends on everything else (if you see what I mean). In some ways you are an adult, in others - you are not. It needs sorting out. As it stands these days I think (please check) that you are legally able to move from your parents house without permission. I really, really don't advise it unless things are totally impossible (and I don't mean restrictions on your use of the internet etc.).
I'm confused by your last sentence 'if I won't get her into any trouble by doing this'. Are you entering into a Lesbian or a Heterosexual relationship?
To be completely honest, I think that you are too young to know what you are letting yourself into. Have you thought about paying the rates, the gas (or whatever) bill. Washing socks, undies, shirts? It's not so romantic when you are draping them around the house. Honestly, most of know about this.