Like others have mentioned, I don't think there was any one moment. I'm 35 with 2 small children and I feel OLD. I have RA and Fibromyalgia - constantly tired and in pain. I want to enjoy my family and my life in general. I'm still young and I want to feel that way!
I was healthy and athletic when I was young. I started steadily gaining weight in my early 20's and haven't stopped. I've tried dieting and exercise. I even worked with a personal trainer and completed a 10k Mud Run 3 years ago at 210lbs. I was (somewhat) strong, but still fat! After the RA diagnosis, I can't work out like I used to so now I'm not even strong:( And I'm even fatter.
My mom died when I was 10 from breast cancer and her only risk factor was her weight. She was only 39 when she died. I don't want my kids to grow up without a mom. I guess that's my final straw - I want to be there for my kids and I don't see that happening if I continue down this path.