My family probably knew, or at least assumed something like that before I ever told them. And telling your family is hard even if you are sure they at least wont throw you out or something.
I was pretty sure they would take it well before I told them. I say you should be prepared for any reaction, but at least have an idea of how they'll probably react before you tell them, and see if you're fine with that.
My parents were quite okay with it. Too okay. A bit reluctant to talk about it, and my mother dismissed it and wont mention at as if I'm straight as long as we don't talk about it. But she has always been scared of something mental or medical being wrong with me, and for my own sake.
The only one surprised was my brother-in-law, I found that reassuring actually, that someone had reacted to it in any way.
It was a bit difficult for something so big to be dismissed, but I'm fine with them not talking about it, I still do if I feel like it.
As for friends, any friend not able to take it, isn't a friend worth keeping. Still, this might be even harder sometimes. First time is worst, and second isn't much better, but lately, it's been really easy for me, natural almost.
Though, if you REALLY want to keep a friend you aren't too sure how would take it, you should wait, and maybe try to check out his/her stands on such matters.
Sorry for ranting.