Sarah is 18 years old. No matter where she lives in Canada, she is fully responsible as an adult for any contracts that she makes.

In Canada, the age of majority, which is when an individual is considered an adult for most legal purposes, including the capacity to enter into contracts, is either 18 or 19 depending on the province or territory. Since Sarah is 18, she is considered an adult in most provinces and territories and thus fully responsible for any contracts she makes.