Is she insecure about me or just an insecure person?

I would say that she just nervous because she really likes you and wants you to ask her out. I'm sure she was just joking about you kidnapping her, everyone has a different sense of humor and hers happens to be a little off to what you like right now. As you guys hang out more and she find out what you think is funny she'll adjust. It took me like a year to figure out what my man thought was funny and what I think is funny is still off from my man, but I think it adds to the relationship.