Let's do the math:
Three classes for the BS 10,000 (which I would absolutely do... too close not to)
Flight training from 0 hours at ATP 60,000
Let's say to get a part time job to cover food and rent for the year it will take you
So, all up around $70,000.
I am not sure which GI Bill you would be under, but I enlisted about the same time you did. If I recall correctly, I got around $18,000. So, let's subtract that: new total $52,000 (note the rules for flight training different than regular school).
After you finish, you will spend the next year living paycheck to paycheck working as an instructor, or other "time building" job.
Now you are 43ish.
Your first regional job will pay $18-25k, will require you to fly out of the worst base in the system, and will keep you away from home 20 days per month (maybe 25 depending on how bad your commute is).
You will NOT get to a mainline without PIC time (unless you know where the skeletons are). So, IF the 65 retirement really kicks in and IF there have been no items to cripple the industry, you MIGHT be able to upgrade in 3-4 years if you are LUCKY (if unlucky, it could be several more years, but we'll be optimistic).
Now you are 47ish finally making $50-60k. A couple years later, you are competitive for the majors.
Now, you are about 50.
Back to the original cost. You spent 52,000 CASH ten years ago, basically lived hand to mouth for seven years, and have only really been making a decent living the last three years.
On the other hand, let's say you took that 52,000 and invested it making a very modest 7%. In the yen years you worked and just started to have a nest egg, the 52k would have DOUBLED to over 100l! at 10% it is close to 140k. Also, if you took a job today that started at 30k per year (TSA starts at 31) and had a few raises to say 50k, you would have earned around $400,000. In the same period, flying would have maybe earned you $200-300,000.
The net is flying will cost you $200-250,000 in the first ten years. Invest that quarter million at until you are 65 and you would retire with nearly one MILLION dollars more.
(if you take out a loan for the original 52k, the cost MUCH more than doubles. at retirement, the difference is 2.5-3 million)