As far as your plant being smaller than others you've seen there are many factors that could explain this.

Strain, indica/ sativa, growing medium, fertilizer, Grower experience and Growing method like topped, supercropped or LST for example.

As for the sex of the plant.

If you have access to a jewelers loop or microscope try looking at the nodes. You may be able to see pre flowers. Some strains will show pre flowers visible to the naked eye while others require magnification.

One last note. Your plant is not fully grown until you harvest it. Keep in mind the flower stretch where you can expect your plant to double in size. Here is a tip for encouraging more branching without topping the plant. Simply anchor the top end of the plant with some twine so that the top few nodes are closer to the ground than some of the middle nodes on the main stalk. The plant will be fooled into thinking the middle nodes are now the top of the plant and concentrate it's growth on the new false top. Once you are satisfied with the new branching simply release the top and it will straighten out and resume growing as the top would.