Please help me.

This makes the third room I've posted this in, but I really need advice. So this is a long story, but please read to the end, I really could use some advice.

I am 16 years old and ever since I was 13, I've been dating my best friend. Like in elementary and even now in high school, she is at my house every weekend or I am at hers. We do everything together. My parents do not know we are dating, and neither do hers. I really do love her. I know that some people will tell me it's just a high school relationship, but I know how I feel. I know that I love her. I know that I want to be with her for the rest of my life. I couldn't imagine it without her. The thing is, both of our parents are EXTREMELY christian and anti-gay. (Not saying all christians are anti-gay, but our parents are. More so our fathers, but both are pretty much set on their views.)

Please refrain from saying bad things about either of our parents, they are very good people, other than that.

I want them to know, but the thing is my parents would make me break up with her. They wouldn't let us hang out ever again. And above everything, my dad would probably never look at me the same. Don't get me wrong, my father has never been mean to me or anything like that at all, but he would be very mad. My mom, I think would be disappointed, but I know she'd be okay with it after a little while. My dad always talks about how if I was lesbian, he wouldn't be at my wedding, he wouldn't support us, and he's never said this but I think he would probably stop talking to me after I moved out. I think he probably doesn't mean any of this, or at least I pray to god he doesn't, and I could probably get him to come to terms with this. My mom on the other hand said that if I was, she'd come to my wedding, and I'd have her support, and all that kind of stuff. I'm super close to both of my parents and I don't want to disappoint either one of them. I just don't want to keep the secret anymore. My dad would tell her parents about it, though. Her parents are even worse about this and they'd honestly probably kick her out. We both want our parents to know but neither one of us want to break up, or face rejection from our parents. Right now, it's kind of looking like we will have to keep it a secret until we're 18 or something, it's just neither one of us really want to keep it a secret anymore. Everyone at school pretty much knows (luckily my cousins have graduated so they won't know.) Can someone please help me?

My sister is an LGBTQ+ ally and I've been thinking about maybe going to her. She wouldn't tell them and I know if it ever got to where my girlfriend got kicked out, she'd let my girlfriend stay with her in her apartment.

Sorry in advance for any spelling errors.