How did we get the specific age number for Age of Consent, Age of Voting, Gun ownership, Driver License, etc.. when age is often subjective for maturity?

Question

Not a pedophile, just wondering.

In: Other

Answer 1

I read it was decided (at least in the US) by the Temperance Movement. I don’t remember the specifics of why 18 was the decided age.
I do know the age of consent was low as 7 in a couple states.