In older Scots law, schildhood was divided into two parts - pupillarity, where you had no independent rights at all, and ended when a girl was twelve and a boy was fourteen. At that stage you entered a stage of slightly greater legal rights called minority. You could not own heritable property (a house or flat), but had some limited rights, including the right enter some contracts, the right to leave school and choose where you lived (forisfamiliation) In 1780 it was stated in Morison's Dictionary "By the common law and prior to the statute 1696, as soon as the years of pupillarity were past, minors were free to act for themselves". Full majority was acquired at age 21, until the Age of Majority (Scotland) Act 1969 reduced it to eighteen.
All of this was finally swept away by the Age of Legal Capacity (Scotland) Act 1991, which granted sixteen year olds of both sexes full legal capacity to enter into a contract.
There are some technical exceptions, but that's a very rough summary.
