And what exactly do you expect to happen from posting this here? Microsoft doesn't necessarily monitor these forums.

Also, given that Missouri is likely one of the only, if not the only, state that grants adult status at 17, it'd be far more trouble and expense than it's worth for Microsoft to make an exception in the Xbox software for that one state. All 50 US states are going to have their own set of laws, as does each country outside the US that the Xbox is sold in, and the idea is to keep things as uniform as possible.

Just wait another year, or complain to a state representative who can contact Microsoft on your behalf. I just wouldn't expect much to happen unless you brib... I mean contribute... A few grand to someone's campaign fund.