There are usually a wide variety of people at AA meetings, from "street drunks" to "business people" in suits. The best thing you can do to "prove yourself" to your GF is to stay sober longterm. You may have run out of second chances, I know I did, but you are on the right track saying that you have to live life for yourself and not "allow your happiness to come from other people." Good luck with the meeting!! Take care.