Uh ya, as I quoted. By and large, because marriage (in the eyes of the law) is simply a legal contract, age to do it is 18 as with other contracts. Most states however allow younger if with parental and/or judicial consent.
Here in Missouri for example, the age for marriage with no one else's approval is 18. (Sexual AoC is 17) BUT, can get married at 15 with only your parents' consent. And there's provision for even younger if with judicial consent.
"Until December 31, 2016--Marriage to victim, at time of offense, affirmative defense, for certain crimes.
566.023. It shall be an affirmative defense to prosecutions pursuant to sections 566.032, 566.034, 566.062, 566.064, 566.068, and 566.090 [various statutory rape charges] that the defendant was married to the victim at the time of the offense.
451.090. 1. No recorder shall, in any event except as herein provided, issue a license authorizing the marriage of any person under fifteen years
of age; provided, however, that such license may be issued on order of a circuit or associate circuit judge of the county in which the license is applied for, such license being issued only for good cause shown and by reason of such unusual conditions as to make such marriage advisable.
2. No recorder shall issue a license authorizing the marriage of any male under the age of eighteen years or of any female under the age of eighteen years, except with the consent of his or her custodial parent
or guardian, which consent shall be given at the time, in writing, stating the residence of the person giving such consent, signed and sworn to before an officer authorized to administer oaths.
3. The recorder shall state in every license whether the parties applying for same, one or either or both of them, are of age, or whether the male is under the age of eighteen years or the female under the age of eighteen years, and if the male is under the age of eighteen years or the female is under the age of eighteen years, the name of the custodial parent or guardian consenting to such marriage."
Translation: The AoC for non-marital sex is 17. But if you get your parent's permisison, can get married at 15 and have sex legally. And younger still if a friendly judge says ok. Usually that's if the girl's pregnant and presumedly, the father not an adult who'd be under arrest for statutory charges anyway. Two hormonal kids who were left alone a bit too long.