Do you know for sure that you can trust your friends? Or, how would you feel if the news that you're gay got out in public? Not that I am suspicious of your friends, but y'know, people gossip.
Maybe invite them all over to your house just to hang out (so it's private and not in a public setting) and then just in the midst of conversation tell them you have something important to say, and let it out. Or tell them when you're hanging out some time, etc, just as long as other people won't overhear if you don't want them to.
It can be scary but it's so much better when you get stuff like this off your shoulders.