Some cultures have it at 16, some 18. Others consider the correct age to be at puberty while some suggest the correct age is when someone is mentally mature, the last line of thought obviously being completely subjective.
What is your opinion?
Is it based on religion or is it based on your own view? Do you think we should have a standard age of consent?
They have to be mentally mature, so I'll go with the international standard age of 18 years when you're considered an adult. Bacha tau bachay bhi paida kar sakte hain lekin aqal hona bhi zaruri hai.