I doubt its an std! She's jumping to conclusions way too fast. Your period is probably just coming. And vaginal discharge always changes so its norma. IF your not sure, get checked out. I doubt its an std!
Periods can range from the color of red,brown,light brown. Different colors may happen and the stink smell is all normal. Don't worry about it. OR you could have a yeast infection. Just talk to a doctor or gyno