How Old Do I Have to be to Author:Fergus Smith This guide is in its 3rd much enlarged edition. It is aimed at children and young people and also provides an accessible guide for teachers, youth workers and agony aunts/uncles. It presents for all the most commonly required topics the rights and responsibilities for various ages from 0 to 21 years of age. Examples of the most often asked (and ... more »misunderstood) issues - how old do I have to be to "baby-sit"? or "to be left alone?" are answered with specific references to relevant law.« less