I can't work out this girl?

So this girl i know has liked me for ages. I know this because it's painfully obvious. Now after a year of knowing her, she recently confessed she liked me. I told her back that i liked her aswell. She told me she wants to see me but she's scared something will go wrong. We started seeing each other, things went well, we kissed a few times, but thats all. Now we had a couple of arguments, and now shes saying she wants to be friends. I said to her why, you've liked me for ages yet now suddenly you want to be friends. She claims she likes me more than a friend but not enough for a relationship. This has really put me in a bad mood, advice anyone???