My reasons are very similar to you... always planned on doing the doc route, but that was before I really explored all medical field options. After looking closely at where I want my life to go in the next 10 years, I decided on the AA route. I've always loved medicine, and because of the scientist in me I am specifically drawn to anesthesia.
As far as your question as to whether you have "enough reason", I think that you do. As long as you know what you want and expose yourself to the career (which it seems like you are planning to do), then you're all set. Once you get an interview, they really focus on your personality and your fit into the program.