When you're emotionally mature and able to handle the emotional, spiritual, and financial obligations that come with having sex. If you're not old enough to be a mother and take care of a child, drive yourself to routinely get tested, or afford the morning after pill (18+), then you're not old enough to lose your virginity. If you wanna lose it at 12, whatever, but when you're 22 and looking for a husband, you're not gonna look much like wife material if you have been with dozens of men; I say dozens because once you have sex, it is very hard to stop. And most young relationships don't last long, so before you know it, you're sleeping with every boyfriend. And those numbers add up. Screw what society says! There's nothing sexier than a virgin- a woman with high enough self-esteem, self-respect, and self-control to abstain. And you will be top pick for wife-material when all of these fast boys turn into grown men seeking a wife.
If you gotta choose, choose to be wife-material. Not miss-right-now.
I lost it at 13. I've always thought it was way too young but the boy I lost it to turned out to be the man I married so I guess it all worked out. I think too young is under 16/17 and there never can be a too old.