Why doesn't my girlfriend ever flirt with me?

me and my girlfriend have been dating for about a month now but had a thing befor that for a couple of months, we have had sex many times and she isn't shy or nervous, i asked her. And she never flirts with me when we text or talk on facebook. but if i call her cute sometimes she would say im cute to btu she never calls me babe, baby, cutie etc.. and she never makes the first move to anything like holding hands or kissing, it kinda bugs me because i like to flirt so please HELP ME.