Why am I getting paid much less then other people?

Ok i work as an intern for GE, i get paid VERY well so i though, but here's my situation/question. this is my first internship and im getting paid $15 an hr. that excellent i know, but there's this other intern in my building who is also on her first internship here and she's getting paid $19???? i did the math correctly "i think" for every two weeks, i get paid $896 and she's getting paid $1200+, now how the Eff does that make sence? I am 20 years old and a male, and she's 21 years old and a female, would that affect anything??? if so then thats bull sh**.