well, you shouldn't have to worry too much whether it's male or female, because even if it is a male, you have no other plants that will get "pregnant".
Just keep watching it, and keep it going until you know for sure.
As for your yield, a lot depends on what kind of light you have, the temps its at etc etc. I am very happy with 2 oz of finished product on one plant- I generally have 9 lights under one 1000w HPS. It is generally an accepted fact that a plant will more than double in size from day one of flowering till harvest. So, if you want a plant to be 4 ft tall when finished, you better put it into flowering when its about 1 /1/2 ft high.

SN