Are they supportive? How do they speak of the LGBT community ? These should be good indicators of their opinions and positions. Share a few stories of your friends, celebrities, etc. Do you have gay acquaintances in common? Talk about them. If you are unsure of how people around you would react, gauge their opinions discreetly. Besides, don't you want people to support you instead of merely shocking them?
Be sure to come out in a peaceful environment for your own peace of mind. This decision should come from positive thoughts, not in a fit of anger or sadness.
