Best advice here is ghettogrower, dont throw her out, wait it out. Dosen't even look like a preflower to me so you gona have to wait it out. I have had some pretty weird preflowers on female plants over the years so nothing is ever conclusive till you see those white hairs or LOTS OF POLLEN SACS, not just one or two!!! To early to tell dude and shouldn't be too worried about sexing it in the veg period yet. Good luck, post us pics in few days.