I was interested in complex systems. Most complex systems live in physics (atoms and galaxies) or in biology (you). The living ones are my favorite. :) Computer science became a way for me to explore and play with complex systems, where worlds can be created, torn down and rebuilt (sort of hard to do in real living systems). We can simulate things that we cannot actually build, and may not yet even fully understand. Look at how far we have come with recent advances into neuroscience and genetics that were brought to us by hackers. :). That is why I got into CS.
An AI simulator to replicate behavior of a human operator in a security domain.
The next steps in AI. We have now arrived at a point where old algorithms (reinforcement learning, search, clustering, etc) have been flying high, enabled by large volumes of data available to them. I'm excited about next steps, where we can develop new ways of working with that data, hopefully inspired by the way actual living systems process and manage information.
The odds are in your favor. Don't let the fact that you are often the only girl in the room discourage you - most people in the field are interested in doing interesting work and sharing it with others, whatever their background. Create good work that interests you - that work will become your calling card, and it will represent you better than just your name and gender. :) It will help other good coders and dev teams discover you through your work. Great teams value everyone who brings good ideas, enthusiasm and expertise, and there are lots of great teams to choose from. Do what you like and let your work lead you to your tribe. :)