if they call u an adult at 18 then why this?

Question

why do they put a thing together for age lets say 13 to 18 and not 18- whatever adult age why does that age group 13-18 have to be with minors under 18

Answer 1

Presumably because if you've only just turned 18, you may still want to be with your friends in the same class at school who have not yet turned 18. My guess is they use 18 as the overlap year: permitted in the adult activities, but also welcome in the teen activities.

Answer 2

because they are ...minors thats why ...under the age of 18 ....if the "adult age" was 25 then if you were under 25 you would be a minor..not an adult