My mom made me confused

[Aroura]

I was with my dad at the Catholic Church today and when we got home my mom talked to me about spiriuality. She's moderate, she doesn't believe in Hell, she's a pretty open minded person. She started the talk, because dad is kind of insistent about the catholic faith (he's not forcing me, he's just insisting). Mom said that Christianity has rules for living a ballanced life (not all rules). She told me again about that "imagining that a God exists thing", that you need to believe in something in order to succed in life, that you need rules. I as an atheist don't believe in a God, I believe in myself, I believe that there are good people, I believe in equality and many other things. Religion is not my main source of rules in life, I make myself my rules (not that my mom doesn't it too, she just relies on religion more than me), I hear different opinions and sometimes I agree with Cristianity. She also likes the rituals at the Church, but I don't. They seem so strict and outdated to me. I must bow down and show humility, this makes me feel like a servant or even a slave. I know that it's wrong to be arrogant and I know I'm not perfect, I don't need to be reminded that. she feels that going to Church makes her part of something, but I don't. I rarely talk to anybody in Church and all the people around me are closed within themselves. They might be happy, but they don't exteriorize it.
It will be so hard to explain to her that I'm atheist. It's not as hard as for atheists who have fundamentalist parents, but it will not be easy. She said that she wants me to be happy and find my own way, but at the same time she's so attached to religion.
She also said that homosexuality is wrong, though she does believe that homosexuals should have the right to live. she's against gay adoption, because a child needs a male and a female role models. Are there any studies that show this? Her opinion kind of makes me uncomfortable, since I might be bi.

There are not enough studies to support any conclusion TBH, but what few have been done haven't shown any greater risk to the children.  As matter of fact, lesbian parents specifically show a much, much lower risk of abusing children.  Nothing shows that male and female role models are necessary, only that good role models are.
There are so many children in need of homes, there is no reason whatsoever to keep gay parents from adopting.

There is also nothing wrong with being bisexual.  I don't know what to tell you about how your parents might feel about it, except to find people who love and accept you as you are.

Best of luck.