Should I come out?

I’m 13 and considering coming out I know my parents will accept me but I’m not sure about my super religious grandmother and the rest of my extended family. I’m worried less about my relationship with my family and more about my brother, he’s younger and if I’m not accepted will my brother feel backlash. And school I go to a private school in a small town so if I come out parents and their friends will know in days. Everybody will know and I’m so freakin terrified. Most of my family lives nearby and we spend a lot of time with them even more in the summer, what do I do. For by birth day my grandmother gave me a bible with a bunch of homophobic crap in it. I’m also worried my parents will say that I’m to young to understand this, I’m not and I know what I am.