I started when I was 15 also and had the same plan of having everything done when I graduated high school. It is possible if you fly everyday. I chose to spend more time receiving quality instruction and building more time necessary than the time required to take each checkride. I got my private when I was 17 with almost 100 hours due to having to wait to turn 17. Right after I turned 18, I got my instrument. After getting my instrument I would fly everyday after school (usually with some friends from school) and GO places. Built up xc, pic, and total time for commercial. Got commercial single and multi the summer after graduating high school. Got CFI and CFII shortly after that. I'm a new hire at a regional now at the age of 20. Most regionals are looking for you to be 21 when you get hired, who knows what that will be in 7 years.

The reason I share all this is so that you can see it is possible and is a good plan. Focus on quality of instruction and time. Fly as many airplane types as possible. And most importantly, Have fun! Don't let your grades slip because of flying, either.

People will tell you it is all about who you know in the industry! Meet everyone you can around the airport, shake their hand and make a lasting impression. My contacts in the industry have allowed me to fly some awesome airplanes and build some great time, as well as getting me hired where I want to be.

Good luck and keep us in the loop with your progress!