I'm involved in a similar group at my school. All my experiences have been great, and we have a pretty large number of active members. I am lucky to have a pretty liberal school-district, though. If you do get involved, I think the most important thing that we stress is that we host a "safe place," as in everything said, asked, discussed at the meeting will stay between the members. Plus, sign up is completely anonymous. Just focus on making all people feel welcome and appreciated.
What's pink and green and flies all over?