Having been a member of a local sorority, I know exactly what you mean.
More than a year after my local was founded, the director of Greek Life at my school was giving a presentation. In the course of the presentation, he said, "There are four sororities here." There were, in fact, six sororities - 4 NPC orgs, AKA, and the local.
Our president was sitting in the front row, and she cleared her throat loudly. The director looked at her and said, "...oh, and you guys." And he went right on talking, without correcting his earlier statement.
Once you've been around a while and had a chance to make a good positive impact on the community, I think you'll be fine.
