Zeraph

Ideally (not saying it could work at the moment) there should be no age related laws at all. Just tests for said activities. The rest have to do with responsible parenting. Laws can't change that. Laws are not a substitute for wisdom and guidance.

Want to take part in politics? prove that you know something about it. Nothing too difficult, just be able to name a few presidents, name a few important laws, that kind of thing. Pick some multiple choice answers about how the government works. If you can understand what's going on there's no reason you shouldn't be able to vote.

Want to drink? Up to your parents. They already control the rest of your safety, why is drinking so special?

Want to drive? Prove it (IMO the test should be harder though).

Sex? Up to you and those that take care of you. No, that doesn't mean 40 year olds will marry 12 year olds. There are still (not sure what their name is) laws that take into account state of mind. If a 40 year old sleeps with a 12 year old the kid was almost certainly taken advantage of and the 40 year old can still be gotten for a new appropriately modified version of statutory rape or those state of mind rape laws. But 12 year olds that want to sleep with other kids? Why not? It'll be the same as it is now. My friends and I started having sex in 8th grade. The responsibility is still on the parents. The law or lack of wouldn't change that.

Military and such would be state of mind and physical related. They already have those tests in place. Just need to add a bit to the state of mind part and make sure they're making their own decision.

Everyone matures at different paces, physically and mentally. Arbitrary age laws are worse than none at all because it gives people the illusion that they don't have to take responsibility for their kids. That the government and FCC will do it for them. And they are arbitrary. Plenty of other working countries have much much lower age laws or none at all and they work fine on that fact.