I want to come out to my parents and my older sister, but I'm not sure if they would be completely accepting of me or if they would even take me seriously. For starters, my mother is Christian (not devout, but still). My father has said before that any father, including himself, would be "disappointed" if their daughter came home with a girl. I would think both of them would tell me that I'm too young to know or some other crap like that. And my sister... I want to tell her because I know for sure that she'd be okay with it, but I don't know if she'd tell my parents without me knowing or my consent. Or should I not tell them at all? I'm too weak to make my own decisions, please help me...
Understand your feelings but don't know how to help. My parents would understand completely but I have hidden me because of how nasty some family and my small town community are about things. I can say I give you 120% thumbs up for the strength to want to tell who you are at 14. I knew who I was by that age but was terrified and terrified to think of sharing with anyone. Love you first and best of wishes!
I would assess the dangers first. Is there a real risk of you getting thrown out? If so then there is no harm in waiting. However, if you feel that you're not under that much threat then you could tell them. If you find that they're not understanding or are disappointed then maybe give them some P-Flag documents or self help books for parents who children come out. This could help them understand and come to terms with your sexual identity Good luck!
If you really feel the need to come out, then I think you should. It doesn't sound like your parents would take it too negatively, even if they're not completely accepting. Being disappointed is not the worst reaction, and they'll get over it eventually. If you think there's the possibility of them really turning against you though, then it'd probably be better to wait until you no longer depend on them. As for not taking you seriously, that's a possibility, but it's absurd to think that someone can be too young to know their sexual orientation. Especially since that only applies to non straight people, no one ever tells a straight person that they're "too young" to know they're straight. I'm not sure what else you can say if they come up with that argument though, I'd just let it be ¯\_(ツ)_/¯ If you do decide to come out, I'd suggest to maybe tell your sister first though. If you asked her to not tell your parents because you want to do it yourself, wouldn't she respect that?
I think your parents will come around if you tell them. They grew up in a different time and mainstream acceptance of gay rights started maybe around 15 years ago only. So I think they will eventually accept you but as you said, it will take them some time I think telling your sister first is a good idea. Seeing that she's ok with it, and if you two have a very close relationship, I think it will be probable than she will keep your "secret" for a while =)