i remember my first period being super overwhelming. i had no idea what to expect and it just showed up one day.
i swear so many girls think they're the only ones who are clueless about this stuff. okay, so basically your period is when your body sheds its uterine lining every month.
try keeping some pads or tampons in your backpack or locker, just in case, and you'll be way more prepared than i was – and that's a pretty good feeling.