I am currently an instructor and recently went through the whole training process. I also worked as a ground handler for a regional for 4 years. I have some advice which is all my own opinion. And by the way it's 16 to get a student pilot certificate and you must be 17 to take the private check ride.
a degree is a must in the long run, you will not need one to be an instructor or get a job with the regionals, or most other time building jobs. The regionals are very desperate for pilots and taking candidates who have the bare minimum requirements.
Do your training through part 61 not 141. You will save a ton! Of money and I always recommend to my students to major in anything but an aviation degree. The majors will absolutely love if you have an engineering degree or a foreign language degree. The only benefit of 141 is a restricted ATP.
As for a job after training, most flight schools hire you after you get your CFI. But there are no guarantees.
As for ATP, I don't know much about them, other than what I've read. But there connections with the airlines is irrelevant, if you get to your ATP minimums and don't bust your check rides you'll be able to interview with any regional you want.
And for starters, all the FAA books are available online, have her start reading the pilots handbook of aeronautical knowledge, just google it and start from the beginning.