Virtually all states allow a minor to enter into a contract but the contract can be disaffirmed by the minor only. In other words, her mother cannot demand they cancel the contract, only her daughter can.

Some states will not allow the minor to disaffirm the contract if they have misrepresented their age. There are other provisions as well and it varies from state to state. So this is not as clear cut as it seems.

Minors can enter into contracts for necessities, including food, clothing, shelter and medical attention.