Sex outside of marriage is unpure and a sin.
{although i dont remember where}, sex in marriage is pure and honorable to God.

It's true, in bible times, girls did get married earlier. but i think time has changed that. society today, is basically telling us that sex is the "cool and fun" thing to do at our ages, (14, 15, 16 etc), but i think that the proper age for getting married is around 18 or 20. and any earlier than that, i think that the person just isnt mature enough to know if they're actually ready for marriage. {no, i'm not saying that only 18 and up are mature}.