Legally a student must be 13 years or older to begin training. We recommend parental permission if you are under the legal age of adulthood in your country but do not require it. If you are under 13 and want to train, we must have parental permission. This is a legal issue, and not a judgement on your maturity or ability.
Of course, there is no upper age limit for training. No one is too old to begin training here, no matter what Yoda says!