I was in great shape in my early 30s, (had visible~ripped abs from my teens up to 34-35) but i did fear aging a bit (how i would look 40+) when i was 35 and lo and behold, the physique turned to shit in my 40s!
i sure didnt peak in my 40s i tell ya that!
Lots of reasons though, if i took care of my body better and didnt react the way i did to all the personal tragedies, deaths etc im sure i would have trained more and thought more about what i was eating.