Family won't accept me? Are they right?

Okay, so I am 13 years old and was raised Catholic. I lived with my grandparents up until I was 7, then my mother and I moved into our own house. My father and mother were engaged but never married... I used to get driven up to his house to visit him every weekend by my grandpa up until I was about 10. Then I realized how selfish and lazy my father was and yeah, I stopped visiting him. He doesn't pay child support either. Anyways, so I my mother has always worked two jobs, I rarely see her except for on sundays. On her days off she totally ignores me. She has always spoiled me and gotten me everything that I want. But yeah, she was an alchoholic for four years up until last year. She would hide the alchohol bottles and lie to me about things.. then spoil me to make me feel better :P. So yeah, my grandpa is the one who watches me all day, and always has since we moved out. He drives up to my house every morning and is my teacher for homeschooling. I have been homschooled for two years. But I have been having problems with my grandma, regarding religion. Since my mother was drunk every day, especially on her day off (sunday), we never went to church for years. She would lie to my grandma and say that we did.. or come up with some excuse about being sick or something. Now that she is sober, she is beggining to go to church, and yeah, I have a problem.. I don't really believe in God. I told my grandma that I didn't believe in God about last month, big mistake haha. I am educated in the Catholic religion, but I have my doubts. I may have not gone to church, but my grandma always forced me to go to CCD classes and read my Bible while my mother was working. So yeah. I told my grandma that I would like to go to a different church... a Christian church.. haha. The people at this church seem more understanding. also, I have recently become vegetarian and everybody in my family has an issue with this. They think that I am a nutcase hippie or something. And my mother wants me to respect her, and she has done farrr too many things that I can not forgive her for doing.. she also backs up my grandma on the Catholic thing. My mother has always given me what I wanted, because she has always been drunk and felt bad lol. Even when I was younger she always spoiled me and wasn't very good at desciplining me. My grandma did that.. there was a lot of screaming. my mother also would basically get really pissed off when she was drunk and I wouldn't listen and hit me. Even now that she isn't drunk she is SUPER mean and yeah I'm afraid of her. They want me to obey them out of fear... which is really frustrating to me. That's like letting them win... it's just really annoying that all of a sudden my mother wants me to listen to her and obey her, when she doesn't even respect me. And my grandma has basically disowned me for wanting to be a Christian not Catholic. She brings up all this "prodestant" crap and yeah. Bad example for catholics.. she's saying that catholics are right and blah blah blah all she does is judge other people too. I'm sure that not all catholics are like this.. but the christians and the christian churches that I know are more accepting and more focused on God and not so much polotics and being fricken controlling. I just want to believe in God.. and I don't know if I should obey my mother and respect her when she doesn't respect me. :P please help, haha.