There are 2 parts of this question, flying concerns, and career advice. The best advice you can take is to isolate the 2, and you can only do that by focusing on flying.
My very first question is: Where are you located? This board tends to cater to US pilots, and if you are in the US, and you want to be a professional pilot DON'T TAKE THE LOAN.
First, you need to get over the discomfort of flying. I was 30 when I took my first flight, and I had the same feeling, but I wanted to keep flying, so I did. I overcame the fear by researching "What could go wrong" and studying how to avoid it.
For example, you specifically mention the fear of "Falling out fo the sky" (I had that too), it's a legitimate concern. In aviation, its called a Stall. Finding the right term for your fear is important, because when you call it "Falling out of the sky" its some ambiguous fear that cannot be addressed, but when you call it "A Stall" you realize that the PTS (and therefore your CFI) will address it as an area of emphasis so not only will you be taught to handle it, you will have to practice it until it is such a non-event that you "Fall out of the sky" on command, and then recover (it actually becomes fun).
The other concern is the loan, $81K means that you are choosing a career for the rest of your life at 16. I think that is a mistake, but even if it wasn't a mistake because you will be so committed to a career, it would still be a mistake because at 16, getting all of your ratings for 81K, will actually delay your entry into the airlines. Why? ATP minimums require that you are 23 to obtain the ATP license, but if you qualify for R-ATP, you can start your career at 21. And you can only qualify for R-ATP if you attend a qualifying program (
https://www.faa.gov/pilots/training/atp/media/Institutional_Authority_List.pdf) and most (maybe all) programs only apply if you enter with no more than an instrument rating.
My advice, talk to your parents about completing your Private Pilot out of pocket (or maybe with a much smaller loan), while working on that, research R-ATP programs and decide if that could be a better solution. If you want to go the airline route, and can log some time, and complete some core college credits like intro English, Math, and other core classes through AP, or Dual enrollment, you could have an R-ATP at 21. Not only would that save your parents the 81K loan, but it could also mean 2 more years of airline flying for you before retirement, which could be worth hundreds of thousands of dollars at the end of your career.