Not sure why it is short. Did you cut it that way? You can add fabric to bottom doubled with batting in between. It will be fine. How are you finishing the edges. I usually finish with binding. Are you closing with zipper? It looks very nice and I am sure she will love it. I make several of the jackets each year. I like how you did yours and if you don't mind, think I will try your piecing next time. The colors also look "rich". Good Job!