No that is illegal.
NOTHING
legally no that is basically robbing the cradle, if you know what that means, and why would you want to marry a 18 year old girl if your a 15 year old boy anyway?
Dress up all fancy
An 18 year old girl can marry an 18 year old boy even if they are not in love in this state.
A girl should marry between the age 20 to 25 years. A girl should marry one year after regularly meeting the boy whom she loves.
In most countries, no.
Of-course they can!
With their lips.
No.
if they both have parents consent
She Doesn't. Your too young.
With parental consent, yes.