Congratulations, you won the generic lotto. Health prevention improved a lot in our lives, but there are still illnesses that you can't prevent and just come at 30-40 already.
If I hadn't kept fitness and eating healthy as a priority for the last 15 years, my health would've been in complete shambles by now. I was pretty lazy and self-destructive through my early adolescence, and in my early twenties I was in terrible shape physically and had a lot of severe mental problems that I no longer struggle with. I'm extremely grateful to my 22-year old self that decided to try and turn things around, it didn't happen overnight.