Of course I didn’t think that you meant little girls, but the fact is that even little girls are thinking of marriage ALL throughout their childhood. I don’t think girls in school are as introspective as you think they are. Their teachers are too busy telling them what they should be thinking. They are busy telling them about the wonderful world of supporting their husbands in Yeshivah (but not giving them the info on how they will do that whent hey are busy having children, or who will raise those children if they are out working while thier husbands are not). That is not introspection in any way, shape, or form. We know what that is. And if they choose that lifestyle, so be it.
Boys are being encouraged to only sit and learn. They are actively discouraged in many cases, from becoming better-educated secularly, in order to earn a professional parnassah. And you can talk to a boy until you are blue in the face from the time he is three, if you want. He will still mature at the same rate that most normal boys mature, and that is not usually at 17-18. You know who matured early? – the boys who grew up on farms, in the shtetls of Europe, in places where boys AND girls had real responsibilities from the time they were toddlers. They learned how to be mature, because they had to grow up quickly. Our kids today are not mature, I am very sorry to say. They are spoiled and pampered, they are fed unrealistic ideologies about their future, and told that this is the best way for them to live their lives, when in fact it is teaching them to be non-self-reliant and feel a sense of entitlement. This is a whole other discussion, of course, so I am stopping here. Maturity, it is NOT.