The younger the better!!! Some people have a higher flexibility range by genes.... I started karate young and am very pleased with myself, at age 30 I can still put both legs behind my head and reach 14+ inches past my toes... Jiu Jitsu helped.... I cannot do full splits, but i can lift my foot a foot over your head... LOL

Younger is best, I just don't recommend heavy weight training of course, it can stunt growth. That might be why I'm only 5'9"..... LOL

Contortionism looks painful to the audience, but for someone who has a high degree of flexibility it can be a fun way to relieve stress and keep in shape. A contortionist bends and flexes her limbs in dramatic ways. You can watch them at circuses and in acrobatic acts. Try some routines yourself by following these steps.
1.Do gentle stretching exercises daily before starting any contortion routines to increase your body's flexibility. A love of movement is essential because you'll put in hours of training once you become a contortionist.
2. Find out if you're a front bender or a back bender. This depends on what direction it's easiest for you to bend your back. The routines you develop hinge on the type of bender you are.
3.Begin with warm-up exercises. For example, stand with your feet shoulder-width apart and gradually bend forward. Grab your legs near the ankles and pull yourself forward so that your head gets as near your legs as possible. Repeat this exercise at least 10 times.
4.
Step 4

Arch your back and round out your stomach as much as you can. Initially use a piece of furniture or a door for balance. Once you gain more flexibility, place your hands on your buttocks as you lean further back. Travel with your hands down your legs so your head is at your buttocks.
5.
Step 5

Move on to stretches only after you've done 15 minutes of warm-ups per session. These include backward and forward bends, doing the splits and manipulating your limbs. The Contortionist's Handbook (see link in Resources) is an excellent training guide.
6.
Step 6

Start training for an hour a day, then build up to three hours. Set aside an hour in the morning, afternoon and evening. Dividing your training throughout the day maximizes your flexibility.
7.
Step 7

Practice your contortionist exercises daily. It can take you a week to get back to your level of flexibility if you take even one day off. Miss a week and you could be dealing with a setback that will take a month to make up.

Tips & Warnings

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Medical studies show that contortionists enjoy better health than the general population because they constantly move their bodies.
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You'll notice your joints feel stiff if you skip a day or two of practice.
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Avoid eating 1 to 2 hours before training.