Are adults still able to reach a professional level in contortion? I heard that one has to start in early childhood?
Sure, your contortion training should start very early. I would say that it is good to start with gymnastics, ballett, yoga or stretching when children are about 8 years old. Most important is the awareness of the movement in general: learning how the body works and learning coordination as well.
I have started my education in ballet as a six-year-old. First I trained once a week and later, by the age of ten, at least three times a week. I did acrobatics as well, and later went on with lots of other dancing styles. As a teenager I trained daily.
After many years as a professional dancer, I decided to learn contortion. I haven’t done handbalancing before neither acrobatics or overstretches. But within six months of an intensive eight-hour-training in China, I reached a professional level as adult in contortion. So, in my case, with the dancing career I came from, it worked very well.