Welcome to the forum, the age question is commonly asked. I recommend checking this thread posting by Adam along with the others in FAQ section:
Furthermore, training at ATP part-time does not exist, there are only two programs: “Zero-to-Hero” and “Credit Private.” The training you receive at ATP is accelerated for what would take a 4-year University/Academy into 7-months…can’t beat that timing elsewhere.
The industry is constantly changing, who knows what they pay may hold in 2-3 years if you started training tomorrow, right now things are trending upwards slowly, but surely. There are Regionals out there paying almost a FO at a Major/LLC airline. Though Chris’ article is a few years dated, it still holds truth into what airline pilots make. Realize that during your time building job, you won’t be paid the “best” of salaries, it’s an entry-level job for a reason