Legal age limits are a mystery to me. According to the US Constitution, you have to be 35 years of age to be the President. The age minimum for being a Senator is 30; you can be a member of the House of Representative if you're 25.
You have to be 21 to drink and 18 to smoke. You can't get into an R-rated movie unless you're 17, but you can drive in fourteen states if you are 14 years old. Texas will let you marry with your parents' consent at age 14.
Let me see if I've got this correct: You can get married in Texas three years before you can go to an R-rated movie, seven years before you can drink, and four years before you can smoke.
Does that make any sense to you?