I highly recommend mechanical engineering, especially if you are more interested in dynamics (motions). I doubt that it is easy to be a female engineer in any industry and I think you should stick with what you find most interesting. Mechanical engineering opens you up to almost any type of engineering job. Any company that does any kind of engineering work always needs a mechanical engineer. For example, I was hired by Lockheed Martin as a mechanical engineer and went on to work as a aeronautical engineer for them. Mechanics is the basic stepping stone for all engineering disciplines. This gives you the most options for your future. Plus, if you already feel an affinity for mechanics you will find it much easier to stay with in the future when things get tougher to understand.
Best of Luck!
Kara Cox