It is great that you are looking into this at such a young age. Those that seem to do best in this career are the ones that start the earliest. I know several guys that upgraded to captain weeks after their 23rd (earliest legally allowed) birthday. They completed their degrees while flying and by the time they are 25 will have all of the requirements that the mainline airlines are looking for and had the added bonus of enjoying a nice chunk of their 20's making a live-able income. If I were to do it all again, I would probably go that route. I am a check airman and recall a time i was flying with a newly minted captain of 23 years of age. I looked over at this very young gentlemen and could not get over the fact that he is so young and is in command of an aircraft flying 4 miles above the ground, at 400 miles an hour, in moderate icing, at night with 78 souls on board. That is some very heavy responsibility. He did a great job. By the time he is my age he will possibly be a captain at a major. This experience really got me thinking about what the best approach to this career really is.
If I were your age (I wanted to be a pilot but decided against it, got a degree unrelated to aviation, worked for 4 years then went for it.) I would get a job at an FBO. Start making contacts in all levels of aviation. I would plan to get my private license over this summer, get as much flight time as I could this year then get my instrument next summer and try to get as much in the cloud time time as I could my senior year. All the while making contacts through sites like this or just by hanging out at the FBO meeting people with planes. After graduating from Highschool I would go to ALL ATPS and do the 90 day program, followed by instructing (by then you'll have likely made several contacts in the field to help you out) or whatever means you can to get as much flight time as possible in order to get hired somewhere as early as possible. During this time work on a plan to get your four year degree.
I would then try to get on with a growing airline. If it is a regional, find a place that has a union contract (this is quite important for reasons that can be nebulous before you enter the industry but are crystal clear a short time afterwards). Picking a place that is growing can be very helpful in your career progression especially if moving onto a mainline carrier is your ultimate goal. The reason being, opportunities to upgrade to captain, thus logging airline pilot in command time, will come much sooner. Think of it this way: for every year you get to the mainline sooner is 200k a year of earning on the back end of your career when you arguably will need the money the most.
It is also important to understand that there are so many uncontrollable variables in aviation that even the best laid plans can go sour, or purely by chance you could end up in a great situation. Just be open and flexible and understand that setbacks do happen but to never give up!!
Definitely heed everyone's advice to try to minimize your debt if at all possible. I took out the standard 80k loan to get done quickly(because of starting later in life). My first few earning years did not allow me to pay my loan payments (earning roughly 300 dollars every 2 weeks as an instructor and 600 dollars every two weeks as a pilot, which was barely enough to scrape by), so i had to defer paying my loans. During that time 27k in interest accrued. My loan payments are now $1000 a month for 20 years. This is a heavy burden that you want to avoid if at all possible. It really isn't any fun.
