Atheist

As usual (?), I was watching a soap-opera-like LifeTime movie in this late afternoon. I just watched it about 15 minutes or so, so I am not sure if I’m getting this all right. But I’ll try explaining it anyway:
A beautiful black lady, looked like an elementary school teacher was accused of something, and some kind of board members tried to vote on something about her, possibly something like whether or not she could keep her job or sort of like that. A female defending attorney was giving a speech on the freedom of religion in the US and she said, almost shouting, “And she is not an atheist!” I guessed that the teacher was practicing some kind of religion that was not common and parents of her students did not feel easy about it. Then the attorney tried to convince people that the teacher was just a normal person, not like an “atheist.” The teacher believed in God, but just not the same God other people believed in.
The saying, “And she is not an atheist!” made me think. OK, that looked a whole big deal. But am I an atheist? If I have never given a serious thought about the presence of God(s), then would that make me an atheist?
I was born and raised in Japan. Lived about 23-4 years with no serious thinking about God(s). That’s so unfair, I thought. That’s the system I was in. Nobody really cares about it, even someone I really respect, like my dad and mom didn’t. Do I get judged by my background culture like this?
Honestly, I guess I’m rather in Agnosticism, I cannot talk about something I have never experienced. I don’t even know if I’d be able to know how to experience those kind of stuff. Then people in major religions go like “hmmm, Masami’s an atheist, how could we trust her?” I guess educated people would know that cultures can turn the almost “common” value-system upside down. So I think I don’t have to really worry about someone judging me of that kind. But what about me? I think I should be constantly aware of my culture and background to explain who I am and why I am like this, otherwise it’ll take a really long time to go figure out at once.