In Chamber of Secrets, we learned that the chamber was opened 50 years ago. At that time, Tom Riddle was still in school at Hogwarts.
From the perspective of Chamber of Secrets, Voldemort lost his body 12 years ago while attempting to kill baby Harry (Harry was 12 at that time). I don’t have exact date of when Voldemort started his hustle for power, so I am guessing it to be 2-3 years before Voldemort lost his body.
Extrapolating from the above data, I don’t have any information about his 35 years of life after he finished his school.
35 years is a whopping big period. What did Tom Riddle do during that time? Did he pursue completely different stuff before turning to the dark side. Or, was he busy creating horcruxes and followers since the beginning? Anything from the canon?