18 years of age
No, your intended partner needs to be legally 'of age' to give their consent.
generally over 16 but special exceptions could be granted by archbishops and popes for arranged marridges of minors under a strict set of conditions
Shakespeare married Anne Hathaway when he was 18. She was 26.
18 or 16 with parental consent. In some states 16 if the woman is pregnant.