Really depends on where you are.

Most of Europe the age is 18. Some countries goes as low as 16. In North America, in Canada it is 18 for 3 provinces, in the USA it depends on the state. Puerto Rico is 18. Mexico it’s 18. Nearly all of South America it is 18 with a couple of exceptions where it is 16 and one case where it is 20. Most of Africa it is 18. Asia is mix but China it is 18.