When you're in a loving, committed relationship and both of you want to. I don't believe a legal marriage is truly necessary in today's world, though many prefer to go through with that.
If ur ready 2 have children.
You certainly need to love each other (unless you just want a harem of people), but you also need to think of future parenthood. No $ex is without giving emotions to the other person, and you need to see if you're compatible in THAT way too. Also, make sure to have enough funds to last a LONG time, children are expensive; and that's before college is added in XD.
I'm only fourteen but this is my opinion. Okay, so, I think you should wait until you are of legal age (whatever that age may be for where you live, so for example: England - 16), and when you feel ready - peer pressure is an awful thing and it is easier said than done, but just because everyone else is doing it, doesn't mean you should too. I'm not a Christian so I'm fine with it before marriage (again, as long as you are of legal age). Again this is just my opinion, not forcing it on anyone.
I'm personally waiting until marriage, but if you know that you love that person and your relationship is strong and healthy, i think it's okay.
I'm pretty sure in some places you get married as soon as 7 years old. IDK where, but somewhere. Could be wrong about that because I think I read it somewhere on the internet. Or saw an article and picture of it in a dream. I don't know, I'm weird xD
We talked about this at camp once, and all the counselors agreed that the 'right' time to have s.e.x is when you are mature enough to talk about s.e.x with your partner. If you can't do that, you certainly can't do it. Once you trust your partner entirely, then and only then can you have s.e.x. It doesn't matter what stage you are at in the relationship, honestly.
By "stage" I mean first boyfriend, dating steadily, married, living together, divorced, grandparents past the 50th anniversary, etc.
I think that once your at a reasonable age and both people in the relationship are ready. No one should ever pressure the other person into doing it.
NEVAAAAAAARRRRRRR!!!! Prances around, warrior style. >:D
Honestly, I think it's a matter of personal belief. Whether that be after marriage or before, I think that as long as both (or more, however wrong that maybe, I'm not judging....) are aware of the risks and whatever, then it's up to them.