I guess it really depends on who the woman is, and if you really respect them. If they're your friends, and they know you respect them, then it's not really that big a deal. However, there are some places, where calling a woman, "a girl," will be seen as disrespectful. I was in a college class, and I mistakenly used the word "girl," and was corrected by the professor, who was a man. I meant no disrespect, and I'm not sure any of the women in the class even noticed or were offended, but there are times, when it's not politically correct (PC).
Frankly, I never really much cared for being PC, but I do think you should be respectful. I don't think you should objectify people, although, there are times when people want to be objectified. We are not only emotional creatures, but physical ones too. We enjoy being treated as such, from time to time. Being physical is not a negative thing. Being a chick, isn't even really a negative thing. It's only negative, when you mean it in a negative way and have negative intent.
I'd be careful who you say it to, but other than that, you should be fine. If you're "lady friends" don't mind, then it's probably fine to keep saying it to them.
Best of luck. :-)