Chase is correct - perseverance. You need to start the app' process immediately. It will help if you have a high grade point average, are involved in extra-curricular activities, play a sport or two, do some community service, are a member of some established youth organizations. Letters from community leaders are a real plus.
There are more ways to become a pilot than CGA - though this is the cheapest and preferred method.
Think about it, they pay you to go to college for four years then ask for a simple five+ year commitment in return. Win-win.
You can also complete college on your own then apply for Officer Candidate School. During this time you can be building private flying hours, which will show your love of flying. Every little bit helps.
Caution: The author of this post is a product of the US public education system.