Most likely 18; you would be considered an adult then.
I would wait till your 18 cause then your an adult and should know what you can and cant do with a 30 year old
Of course they can, why shouldn't they?
There are a few countries where you can marry under the age of between 14 (girls) and 16 (Boys). My research gives these results; Kuwait Yemen Colombia Paraguay Venezuela There is no state in America...
as long as you dont have sex till your an adult too its perfectly fine