Mike,
Yenz is talking close to my heart. I live in Wash Co, and flew out of PIT right to the end in Feb of 2008. I now am one of the PIT refugees that commute weekly to other domiciles. I won't say which one yet.
16 is not too young to start. I would however suggest that your daughter think about majoring in Aviation in college. It doesn't have to be Embry Riddle, which is very expensive. The Ohio State University and Kent State both have flight programs. They are well respected and will serve her well.
I she wants to work at a major as a pilot she will need a 4 year degree. Many suggest not majoring in aviation but I can tell you as a 30 year pilot at our former home town airline, that's what they are looking for. The college flight programs allow a person to get the ATP with fewer hours. It is more expensive on an hourly basis but cheaper in the long run.
There are probably many others who will disagree with my assessment of an aviation degree but I know for a fact hat our new company is actively seeking these graduates.
While she is in high school she should work towards her private pilot's license. That will give her an idea of what she is getting into and whether or not she actually likes it and is willing to put up the effort to understand it.