You should never feel like you shouldn't vent because you feel like your problems are are nothing compared to other people's problems. You're problems are important too, ok? ❤️
I'd suggest a calm conversation telling them how it's affecting you in a negative way, they can't really expect you to be like everyone else in your family or even praise the same religion. You have the right to choose that for yourself. If that doesn't work and you get bad reactions from it, sadly you should wait till you're 18 to leave and just be done with that. I guess there could always be going to another home but I don't really know your family situation or if you'd even want that.
I hope everything works out and I'm sorry that I commented late ❤️💘💝💞