I remember coming out in High School. I of course have a younger brother my parents can rely on to carry on the family bloodline and he definitely likes girls. But even so my father was really distant then and he's still kind of awkward about it and well my mother she's comfortable with it now so at least thats good. Not sure what to tell you though, since I don't know your situation but I hope it went well as it could with your mother. Hope for the best and I guess just be yourself...I'm not much of an advice giver...heh.
And I'm going to stop here because I could probably ramble on for like...ever...
Good Luck!