i am pursuing a career in aviation without a degree or a diploma, although it does help when it comes to times of employment but i know of others who have careers in aviation without a degree.
Although, i believe it would look better that if you completed your high school diploma instead of doing the GED. I believe that would be a wise decision.
I think the younger we start the better your chances, but then again dont dismiss the idea of getting a degree, sometimes if everything does not work out it is good to have a fall back plan. it also shows that you are a well rounded person. I may not have a degree myself but i have taken other steps and covered different areas that has given me experience in other areas. But you have a good attitude and you seem to be set and very focused on what you want to do. good luck with it all and all the best.