Help! My 13 year old sister got her first period.

I'm 22, and the guardian of my 13 year old sister. It started one night at 3 in the morning...
Her: "Aj! Aj wake up please"
Me: "What is it? Why are you up so early?"
Her: "Sis I need you to come in the bathroom"
Me: "Why, what's wrong? Are you sick. 
Her: "Idk. My stomach hurts and I might be dying"
Me: *Jumps out of bed* "Holy crap! Nan I think you're on your period.."
Her: "My what??"
Me: "Your period. The thing you call it my 'lady problem'"
Her: "Oh my god, I have to go through one of those too??" 
Me: "Yes. Every female does. It's an <a href="">eve</a> thing I guess"
Her: "Aww, first the boobs, now this? This is horrible"
Me: "It's normal, and you will get used it. I teach you everything."