Get a degree in something that interests you. The only real requirement for most airlines that list a degree or to make you competitive is a four year degree. No airline requires it to be in a certain field which is why many (myself included) think aviation degrees are worthless. Aviation degrees put all your eggs in one basket and that can be dangerous if the airlines aren't hiring or worse, you get laid off as I found out recently. Thankfully I've already been recalled but I had no luck finding a job outside of entry level retail with high school kids (no offense) because the economy is bad and nobody wanted to believe that my aviation degree would apply to their business. If you desire to spend the extra time/money to get a second degree so be it. The most common route to the regionals would be:
Get your private, then instrument, then multi and commercial ratings. Follow that with your CFI. Start instructing. Do that until you have at least 1000 total hours, and at least 100 in a multi engine hours. Those are the traditional minimums for regional jobs. These can go up and down depending on how many people they need and more or less desirable companies as well.
Many were hiring people with as little as 300 hours last year. Right now, most aren't hiring and when they begin again you might need more than 1500 total hours to even get a look. After 9/11 this was the case.
The instructing part could easily be done during college if you have the ability to start working on your ratings while you're in high school. You have to be 17 to get your private and 18 to get the commercial but you could easily have the times I listed above if you are able to start instructing by your 3rd year of college.
Your ambition is admirable, and I hope it doesn't diminish. However, make sure you take the time to enjoy high school. Enjoy college. Don't make your life revolve around the airplane because you'll be no fun to fly with and you'll regret that you didn't get to do all the fun stuff the guy/gal sitting next to you talks about while you're BSing on a long leg. You have the rest of your life to work
