How to write things about women? (that I don’t personally know about)

I’m writing a fanfic where the protagonist is a girl. Immediate problems:

I don’t know how women’s hygiene/clothing works.

Extension: I don’t know how the menstrual cycle works. Actually, I didn’t even notice or remember I had to take this into account until one of my classmates did a presentation on it yesterday.

I don’t know much about women-specific problems. Also, the setting is Kagoshima, Japan. I don’t know anything about the women from that locale or their culture, but I know Japan leans conservative when it comes to gender roles so I’m just trying to write as ‘normal’ as can possibly be within that framework. Without being too stereotypical or anything.

Minor problems: I’m not entirely sure if women interact differently with women than they do with men (I don’t think they do tbh????? But I’m one of the few guys in class who isn’t really all that close to women, so I kinda just observe how they interact with others.) With the protagonist, I mostly don’t have to worry about this because she’s introverted, but I still have to worry about how she interacts with people she’s close with + how other girls interact with her.