What you want to see is going to look like a small ball but it is a calyx. From that calyx a small thread like hair will push out. That is when you know you have a female. They will be at the nodes directly attached between the branch and trunk. A lot of people mistake the early ones for balls. The easiest way to tell the difference is a calyx will be directly attached to the branch. If you look real closely with a magnifying glass, the balls of a male will generally have a small stem attached to the bottom side of it. The calyx won't it will be directly attached. Also, of course, the calyx will begin throwing off pistils. Best of luck with her/him.