Among the fishermen and shrimpers on the Gulf Coast back in the 50s and into the 60s girls would marry when very young but the grooms would be older and making a living already. A mother's ideal for her daughter was to marry her 13 or 14 YO to a widowed boat owner who also owned his own house. After a few years he would die and leave her with house and boat and maybe a child or two, some money in the bank, and she could remarry to whom she chose. In that culture everyone benefited thereby. I have known quite a few such. The bayou community I was familiar with way back when has been invaded by affluent folks in their McMansions who like to live on the "picturesque" bayous. The traditional community is now more like a rural slum, especially since the State and Federal governments have restricted shrimping and fishing to the point that only the big factory boats can make any profit from it and those are of companies that can afford the fees and corruption necessary to work. There are still marginal shrimpers, quite a few, actually, but a mother would not wish her daughter to marry one of them. The only ones that make a half decent living are smugglers and that trade is being interdicted way too often.
That sounds like a workable system. The fact of life is that teens get horny, and it seems better for them to exert that enthusiasm within the confines of marriage, rather than a succession of "hook ups". Living with their parents also provides extra help in caring for babies.
I've been telling my daughters "get married soon after finishing college, because if you wait until 30, the good guys will already be taken".
I can remember when a 16 year old boy was working for a living.