I don't know if I should do this I'm not out and I don't want to be found out I'm sure that if I joined my parents would be told and that would lead to questions...
If you're not ready to be out then don't join. Ppl are gonna be like omg ur gay? You could always be like na I'm straight tho. However I think it'd be a fun group to join and you could find new friends and hangout with people
Most people with a schools GSA won't out you if that's your concern, but I can't speak for those outside of it. You certainly could claim to be straight and just supporting which there are certainly those people. The president of the GSA at my undergraduate school was straight. Personally I find them a great place for support and finding people whom you can talk about all thing LGBT. College is however a very different place than high school. The school that I teach at seems to have no issues with students, but have had some long calls with parents who were complaining about us letting their kid in. Ultimitly it is up to you.