I hope you don't mind a parents point of view, although we are not overly strict with my 16 yo daughter, I have been known as one of the stricter moms.
I would feel very uncomfortable when my daughter used to ask if she can go and hang at someones house. The reason being, I didn't know the kids or the parents. How can a parent just say "sure, go hang out with people I dont know. " I am almost 40 yo. and I know a few parents who party harder than their kids. How do I know that some parents might serve alcohol or do drugs with the kids. Believe me, it happens. I need to know who my daughter is with at all times. PERIOD!
My suggestion would be to ask your girlfriend to ask her parents if she can have you over to do homework, or study. Tell them you are working on a school project together, or something you need to do together. If the parents say yes, make sure you both stay where the parents can see you. Make conversation with them. Talk about anything....the weather, your , politics, hobbies, how nice their house is.....anything. Show them you are a good kid, and try to gain their trust. Be very polite.
It will make it a lot easier to go out (away from her house) if they know you a little.
Its really hard for parents to let go and give their children their own space......Trust is key! You need to earn it from her parents. If this girl is worth it, you shouldn't mind a little bit of a** kissing.