Why should the gambling age be lowered?

Question

We're working on a debate and need reasons why we can argue about lowering the gambling age to 18.

Answer 1

At 18 you can be sent off to die for your country and you can vote.  If they think you are old and mature enough to be sent into war then you are old enough to gamble.

Answer 2

it shouldn't!

Answer 3

Because we need money too and are no different than a 21 year old?