OK, Am I to understand that you are asking fellow LDS members these questions? Do you know these answers at all? What is the purpose of asking questions that you already know?
I am very curious to know, seriously. You are LDS according to your profile, but you don't know these things. Are you just trying to spark conversation, cause these are very mainstream questions and have very mainstream answers. I would be happy to answer them though.
Pre-marital sex- No, but if it happens, repentence process is always an option. The repentance process in this occasion is usually assisted by help of the bishop.
Intermarriage between faiths is allowed of course. However, they will not be able to take advantage of a temple sealing which is marriage for not only time, but for eternity as well. The reason this is not possible is because the individual not of the LDS faith is not to believed to be baptized by the authority of GOD since that authority only exists in only one church which is believed to be the Church of Jesus Christ of Latter Day Saints (LDS for short, or Mormons). A baptism is considered to be an ordianance. The ordinance of Baptism precedes the ordinance of a temple marriage. So without both individuals being baptized, they cannot both participate in a temple marriage, which would bind them for time and all eternity.
So again, marriage between different faiths is allowed, it's just that the individuals will not be able to be sealed (married for eternity). They will marry for time only which can be done anytime, anywhere, by anyone with that civil authority.
Age for marriage has not been spelled out by the LDS faith.
It is one's own personal preference. Best judgement is the stipulation here in my opinion. But if you're like twelve or something, just be ready for the "OH my goshes though." But that would happen in any denomination almost. That's just a human reaction, unfortunately. There are many of those in many arenas of life though.
Engagements are very prominent in the LDS religion. In fact, I think it's a definite occurence. This time however, is mostly used to just prepare for the wedding though. While I've seen others engaged for years on end, you won't see this occur for the same length of time in this faith. Again, it's just used to prepare for weddings. But this is not a religious belief. In all my life, it has never been a teaching that has occured at church. It's just a way that the world works. So there's nothing in our doctrine saying to it or not to do it. It's just one's own personal choice. Along with the length of the engagment.
Marriage is only allowed between a man and a woman.
Marriage is not required. There are many members of the church that go thru their whole lives not married. If one does not marry during their life here on earth, then during the Millenium (thousand years of Christ's reign on the earth). They are still able to marry.
Divorce is allowed. However, it is not encouraged. If two people just can't seem to get along, this is not grounds for divorce. Although, no one will stop them. Marriage for eternity is a very important contract between two individuals and this helps two individuals see the bigger picture in all things. To be honest, divorce shouldn't even be considered because as soon as it is, then justifications for doing it start to pile up.
But if two people can try to never even consider it, then solutions for getting past their indifference are better facilitated and can therefore be attained. When two people understand that their stuck no matter what, then it's amazing to see their sense of resolve. But as soon as people consider that there's another option, then suddenly that option is exploited to the point of actuating it.
However, the church does allow and not discourage divorce when spousal abuse is occuring, or one individual is endangering the life of the spouse or the children. But definitely character indifferences and falling out of love are not looked at as good enough reasons to separate, although again, no one's going to stop them. They're the ones that have to face God in the end and explain to Him that it was too hard.
I hope this helped. Kenny
Thanks.