How to come out?

So I’m 17 and I’ve been questioning my gender for quite some time I would say ever since I was little around 5-6. I know I’m not gender fluid because I don’t remember the last time I was genuinely happy about being a boy. The major problem I’m having is I don’t really have anyone to talk about and recently my mental health has gotten really bad from holding this in. I never ever thought about suicide in my life but recently this part of me is just urging me to come out but me not being able to has caused serious dark thoughts like me just being better off dead. I’ve been on antidepressants for quite some time and I know it’s not them causing this. The only person I feel like I could attempt to talk to about it is my sister because she supports everyone and has a ton of trans and gay friends but I feel it’s a little risky because she’s close to my mom which nothing against my mom, but she’s transphobic. I came here to try and vent, but I wanted to see if there were any discord servers to try and join to help me. My friends don’t necessarily like trans people and I feel if I came out that I would lose everything.