This is my black skirt tetra and its been getting fater and fater and slowing down is she ging to have eggs?

While she appears to be swelling with eggs, there is no guarantee she will lay them, especially if there is anything that would cause her stress (aggressive tankmates, overzealous males, poor water quality) in the tank. Your best bet for breeding her would be to move her and a male into a separate tank and let them go at it. Once they lay the eggs, remove both parents, keep the tank lights out (the eggs are light sensitive), and perform daily water changes-- keep fry food on hand, but do not begin feeding it until they have absorbed their egg sacks.