I had posted it this in reddit but I'll post it in here.

Been trying to find this one anime that i watched when i was young. The mc is a girl with a really reallyyy long braided black hair that it was constantly mentioned by the people around her. It's kinda like rapunzel where she can't exactly cut her hair because it's tied to her power. she's like a reincarnation of a god, i think. Came from a family of priests and whenever she uses her power while her hair was braided, it would come undone immediately. She has a very timid personality and tries not to draw attention to herself.

Another prominent character is her male lead which is this guy that's kind like her bodyguard, i think. He's constantly around her. I'm pretty sure he like dislikes her or something

The story was also set in a modern day japan. The first time she was seen was in her school uniform

I remember this scene where they were at a camp with classmates or probably friends and she accidentally drank wayyy too much of the cocktail with the alcohol. She end up drunk and came to the guy all smiley and happy. Until she fell asleep on his shoulder. And this scene was uploaded into youtube

Did she have white hair and was it like ancient old timey Japan?

Nope. She had black hair. I think she usually braided it into two. And it was modern day japan. She was constantly seen in her school uniform