Some like 'em young...

[Valion]

Well in the ancient world it's not uncommon for this sort of thing to happen, at best getting married to a girl that young is mostly political.

[Tellos Athenaios]

Others would say you approved; moreover that it is a political marriage you (the faction leader) very well might have arranged?

[Ibn-Khaldun]

These kinds of state marriages were common even in the 18th century. IIRC then the last French kings wife Marie-Antoinette were 14 when she and Louis married. Also, usually there was a deal between the father and his daughters soon to be husband that they can't do you-know-what until she is in certain age. These were more states-marriages than anything else.
I have also read that this was not that common in the lower classes though and commoners usually didn't arrange these kinds of marriages.

[Aemilius Paulus]

Wasn't it somewhat normal in the western civilizations to marry the girl after puberty though? I'm sure there were exceptions, but I always thought that the early childhood marriages were more common in countries such as India or African nations.

[Ibn-Khaldun]

Yes it was but it did happen that even small kids were married to each other just to get legitimate claims on someones throne. Though, I'm not an expert on it and this is just something I remember drom the books I've read.

[SwissBarbar]

actually for a girl of the roman high society it would be a shame not to be married. Girls were given away by their fathers with 12-14 years, boys with 18. A marriage was a partnership of convenience, mostly planned by the parents years before the actual wedding. Infertility was one of the grounds for divorce. Feelings dit NOT matter! Actually, love as a reason of wedlock is a very young phenomenon in history of civilization.

in my opinion, the fact, that girls were mostly named after her fathers family name - at least in the time of the republic (gaius iulius caesars daughters name was iulia, the daughter of Gaius Antonius Hybrida was named Antonia etc.etc) shows that they were his property, so he could marry them to whom seems best for the family