Coming out?

Scarlett • Pizza Lover, especially with ranch
So I'm bi, and I'm out to most of my friends and my mom (because she dragged it out of me), and I feel like I'm ready to come out to my school. Every year people make speeches for National Coming Out day, and I plan to be one of them! Here's the thing: I feel more comfortable coming out to a bunch of people I don't know very well than to my dad and sister. It's not that I think they won't accept me, I just don't want them to see me differently. Should I come out to them before the speech or just wait until it comes up?