That's a tough picture to tell from. Based on the 3 lines, I would say girl. But don't take my word for it.
I say girl ;)
I would wait a few more weeks, genitals aren't fully developed until closer to 20 weeks and it can change!
I say girl, it doenst look like my ultrasounds from either of my boys from around that time frame
I would give it a little more time.. :o)