To make my story short:
I met this girl on a club. We talked and at the end of the evening we where kissing.
THe day after (or after some days), after texting a bit, I kinda invite her to have a drink, and she says: "just as friends right?", "no flirting..." and I reply: "Obviously :p"
Later in the chats on mobile I find out she kinda feels guilty for the kiss, using the excuse she was drunk.
We meet one day during a big party together with my friends. She doesn't stay long.
We tlak again some times on mobile.
There is again a big party so we agree to meet there. But because I was going only during the evenings, I didn't manage to meet her (even if we kinda overlapped 1 hour together there).
Today we met again and had a drink at a bar.
Each time I write her, she answers me. SHe doesn't talk much as I do, but I think it's her charachter (hard girl, but shy).
Now I though to invite her for a movie at my home tomorrow evening. Do you think this is too fast? All advices on how to proceed appreciated.

Just do it. Whats the worst that can happen. She says no. Then you know its not worth pursuing. I'm just starting to realize this now. Life is short and opportunities pass quick. Better to have a crack than to sit around wondering what would of happened if I asked that that girl out or I wonder if I made a move on her would she of be keen. Also you can look at it as just more experience to your overall game.