First Off...I think we ALL respect your decision to stop riding. I wish you well!!!
Although we all make decisions in life based on different things we have seen or were involved in, I can tell you that I sometimes think "What If", and shortly after thinking that, I quickly remind myself that I have but one life to live. By no means do I plan on making an early exit on life or try to live too far beyond my limits...In fact, I hope to live till 100. I just realize that when I'm out on my bikes or doing something that everyone else considers dangerous, I do my own personal risk assessments and try and operate within my limits. I also feel like for every mistake (3 street bike accidents that were ALL my fault due to hot dogging it) I have made, I have learned and progress'd forward and have never made the SAME costly mistake twice.
All my kids ride MX and I used to wonder if I was not being as protective of a Parent as I should be. I had to re-evaluate myself, after all, it's not just MY life I'm dealing with, it's theirs, and that would devestate me if something happened to them because of my decision. I even offered them a substantial amount of money just to see if they would bite, well they looked at me like I was out-of-my-mind! They basically told me to pack sand! I also remember when I was a kid their age, we did it for the love and adrenalin. So I decided I wont take that away from them, but I will make sure they are set up for success...I teach them to wear their protective gear at all times, slow is fast (Nobody will become a PRO overnight so ride within your limits), and to ride for EVERYONE else out there too. Because it's almost ALWAYS the "Other" guy you need to worry about.
Not that my experiences will change your mind but I just thought I would share it with you. As far as your decision, I respect it and again, WISH YOU THE BEST!!!