I certainly never said having done sports in the past doesn't help at all, I'm sure it'll help to some degree, despite living a completely sedentary life since then. I was very explicit about my own strengths and weaknesses, and gave my perspective within those confines on how I see the challenge of the trail in combination with what I've read and watched from others on the topic to give one of many answers for OP to take into consideration.

I've met 100s of people on the trail so far, and some of them are only doing a few miles a day to start. Some are fairly old, some overweight, and some injured. I myself have had to completely drop my mileage down to nearly 0 due to injury already, while another person I met has been to the hospital to get cortisone. Now, am I betting that these people are as likely to finish as a triple crowner cruising 20 miles a day? Of course not, but frankly I'm also not willing to bet against the potential for any of them to complete the trail if they continue at it either.

Do there exist people that are completely physically incapable, no matter what? Sure, but I think that is a fairly low percentage of people, and not the "average" adult with no physical training.

Everyone is indeed different. I don't know what wise quote you think I'm adhering to and/or attempting to force onto someone, but it seems you just disagree with my conclusion, which is fine. OP gave fairly little information on their actual health and physical status, aside from having no specific training, so both of us are essentially guessing in the dark lol. Only OP will know what is right for themselves specifically as a result.