It depends on what counts as "getting into drugs". I started smoking cigarettes on daily basis at age 12. Alcohol and cannabis on weekends by age 13. But I would consider my true "getting into drugs" period was when I started using amphetamines and LSD. Mostly mdma and amph sulphate, with cocaine thrown in the mix here and there. I am an extrovert so if that is trait/reason by which is measured I got into drugs from being an extrovert that started partying.
So I qualify as extrovert who started going to trance and techno party's at age 14 and used amphetamines 2-3 days (max 4) weekly. What can I say, 90s were great time for partying. Both music and drug quality was top notch.
But if I had to say the real reason it was the depression that was the real reason for starting and not not stopping using amphetamines at that age.